I have been working on a wildcat cartridge based on the 6.8SPC case that I would now like to share since I am now a short time away from having a prototype to test.

I want to personaly thank H at ARP, Mark at MDWS, Randy at Accuracy Unlimited, Dave at PT&G, Troy at Newlon and Mike at MGP for their help with this endeavor. If it wasn't for these guys I would not be as close as I am to having this project up and running. I am simply a person that has been inspired my Mark and his 277 Wolverine & H with all his work with the 6.8 and other cartridges & Mike at MGP. I am just an individual and have no corporate affiliation so this is all an out of pocket endeavor. It is a passion of mine to try new things and test my abilities in R&D.

That being said, I have, along with the above individuals, developed a 6.8 cased wildcat that I have dubbed the 35KLR. (35"Killer")

The Metric specs on this is 9x32.

It is a 6.8 cartridge trimmed and necked down to 35cal. It is similar to the 35MGP in this way. I, however, designed this cartridge to meet a few diferent criteria.

1) Compete with, & surpass, the 300BLK in subsonic, supersonic and supressed short barrel applications by offering more projectile options and deliver more energy by utylizing a larger capacity cartridge & diamter projectile.

2) Use all mil-spec components that are used by the 6.8. No modifications what so ever will be required. It will be a simple barrel swap and that is it.

3) Offer short to mid-range hunting power for medium sized game that exceeds the 300BLK balistics to just over 150yds.

4) Offer more readily available & less expensive loading options by being able to utilize common heavy 9mm and 35/38 caliber hand gun projectiles at their intended velocities and internal balistics as well as 35 caliber hunting projectiles. In otherwords, maximum versatility in projectile options & cost range.

The cartridge was designed first and foremost as an auto feeder with a min-max COAL of 1.64-2.00" with 125grn-250grn projectiles.

To date I have:

A barrel in 1:14 twist procured that will start in the 12.5-14.5" range and go down from there.

Reamers, gauges and dies are in the works. I should have reamers for the chamber & dies in about a month.

Dies will be custom made Newlons with no expanders and bushings for alternatively loading 355/356 or 357/358 projectiles.

Barrel options I am looking at will be in either 9mm or .358 depending on intended application of barrel length and twist rate. I may condense it to one bore in .357 to cover all applications but offer differing chambers & utilize different twist rates, from 1:10 on up, depending on intended application.

Inside trimmers are also in the works for concentric and uniform necks to offer the most consistent neck tension & pressures.

It is further my goal that:

There will also be preloaded amunition for this cartridge so if you do not wish to invest in Dies and all the work associated with a wildcat, you won't be required to. There will also be a reloading option for purcahsers to send in their used brass and purchase reloads at a significant discount since Brass is the most costly & hard to find component.

I have a lot of testing ahead of me but  will update the thread as testing goes forward & I will post images to give you all a better idea of what the concept looks like.

I am looking for further input or interest so I can gauge receptivenes to what I am working on. Please feel free to offer any perspectives you may have. I will try to answer questions to the best of my ability.

In the meantime here are a few pics to get an idea of a preliminary cartridge & the cartridge with a 115grn 9mm in comparison to a 9x19.

35KLR Cartidge:


35KLR loaded with 115grn 9mm.


35KLR close-up.


35KLR vs 9x19.


35KLR in 6.8 mag.


35KLR being extracted.

I like the idea but the reason 300blk has had its success is because all you change is a barrel. Your round would have to be extremely good when used subsonic, Like crazy good to be considered to be used. Because if its only marginally better but is more expensive and doesn't have the parts interchangeability it won't be able to compete. I'm not saying this won't be a good round but you have a lot to compete with. Do you have any estimates on how much better this should be?

There will be a considerable advantage over 300blk:
More case capacity,  greater selection of cheaper & more applicably suited projectiles & better performance are all in favor of this cat design.

300blk compatibility is only a concern to those that possess a 556 to begin with. To a new purchaser or a current 6.8 owner this is mostly irrelevant. Furthermore those not interested in reloading will be able to purchase ammunition in the price ranges of 223/556. For the reloaders it is even less expensive. Yes some guys who mold their own can get by with cheaper loading but they are far from the norm.

As an example, here is where I think the heavier projectiles will land with the case capacity I am seeing.

180grns ~ 2,100--2,200FPS maybe a hair more.

200grns ~ 1,900-2,000FPS.

250grns ~1,700-1,800FPS.

The 200-250 grains will also be the basis for initial sub-sonic rounds. The majority of the preliminary testing will center around Hornady Interlocks in these masses. Obviously the sub-sonics loads will not be within the expansion velocities per-say, but what their performance will be will have to wait until gel testing.

The biggest problem with the 9mm projectiles is going to be finding a powder/ load density to run them slow enough. I have spent considerable time thinking "outside" the box in order to hopefully run 9mm rounds as low as 1400fps. Some 9mm/ 38 caliber can go as high as 1,800FPS or a tad higher. with 140-160grns in this case that should easily be accomplished. With 6-8" barrels hopefully I will be able to scrub enough velocity to make it work.

I'd like to see subsonic performance in roughly 6" barrels.  I've got an 8" 300 blackout and I've been thinking about cutting it down, I'm just not sure how well it will run.



One of the big obstacles to marketing a .35X variant for subsonic use is that very few people have rifle cans over .30.  Sure they can use a pistol can, but they can't run hot loads through it.

       
 

Why would you run a hot load when using a can?

Pics ?

Sound suppression.  It may not be hearing safe, but it's still a lot nicer than no can.  Many people keep the can mounted whether they're shooting subs or supers.  It sucks if you have to remove the can to shoot your supers.



I have a 7" titanium can coming for my 12.5" 6.8.  It won't see any subsonics on that rifle.



 

Congrats gt on getting your project off the ground... Looking forward to watching the development and results.

Considering the 6" barrels what you are asking is quite easy when you consider the intended application & the bullets available for use in 9mm & 35 calibers.  Being as there are many pistols with suppressors running right at 1,100fps what ever your chosen projectiles performance is, that is how it will perform. This takes a large amount of guess work out of how it will perform if you choose the right bullets for the application.

Beyond that you are simply limited by the projectile itself in terms of maximum velocity for supersonic use. If you want to spit a 150 grn .357 at 1800 fps the cartridge should be able to.

Plans are in the works for this to be available through a class 7 SOT that will be working with me to develop cans for this application as well as ammunition.

I mentioned earlier the 200 - 250grns as being my initial testing but that is for longer barrel applications,  not your intended 6". For 6-10" I will recommend traditional pistol projectiles. I will get around to testing the heavier mass bullets for load development but that will come later in testing. Performance should be the same with a constant velocity as it will translate to the same penetration & expansion regardless of barrel length.

Done.

Thanks bud! Lot of work yet to be done. Should be fun!

Whats it look like with a 125 and a 250?. I would really like to see the sound compared to a suppressed 300BLK (subsonic) and compared to the 300BLK in a ballistics test. It looks interesting though.

Any concerns about feeding Issues considering the rather short COL ?

I will update the original post when I can do a few more cases. Keep in mind these will all be preliminary cartridges as the actual dies are not yet made & does not exactly represent the finished design. They are intended as a visual aid as what I could do with the dies I have on hand to test chambering & get basic dimensions for the chamber.




To be honest there was & is. It was the first things asked by a few individuals involved with the project. Not having a proper chamber yet has led to me testing feeding by hand cycling. When slow cycled it would have a tendency to hang up on the extensions but when the bolt is just let go it would ride over the extensions and drop right into the chamber. From what others have said about testing Stubby 35's in the MGP cat COAL isn't really the whole issue. Stubby 35's, espessially flat nose or hollow ppoints, are pretty wide & don't engage the radiused part of the extensions. It is deffinately going to be a large part of the R&D process as something that will have to be further evaluated. Future plans call for smoothing the extension edges or may require further massaging of the extension. Also the use of a center feed extension has been brought up.

I did a similar thing years ago on a M1 carbine using 10mm magnum brass necked down in a 357 sig die. I think I used the sig reamer run long to chamber. I wonder if I have any parts left. I think the overall length was close to what you have there

That's cool! How did it work for you?

I appreciate the post. The 10mm brass was an option for me to begin with, as I reload 40/10mm, with in the sig specs. The 10mm is a bit shorter than what I have worked out but it can work with the 6.8 bolt if the rim is taken down. The decision to go with the 6.8 case was the fact that many have brass on hand & any less work that can be done is a bonus from either a reloaders or production standpoint.

I considered long loading 9x25 dillon as well but I wanted something more tailored to multiple applications.

it was okay, like a 357mag out of a rifle.  It didn't quite have the ballastics I wanted, but looking back it was more than adequate and I was young and more power then .  The magazines were always problematic, having to heat and re-form the lips and they would still "puke" all the rounds every now and then.  338 scepter uses the 10mm mag brass and it is the same bolt head as the 6.8.  I still have all my 10mm mag brass waiting for a scepter build someday or to revive that project in an AR.  I used a 358 barrel and it worked good with 357 and 358 bullets.  9mm bullets were too small and grouped all over the place.

Is this a "just because" build or are you really trying to make cartridge to replace the blackout?

While it will outrun the blackout no problem is it really enough to constitute going through the additional hardware changes and trying to find already expensive or non-existent brass? You cant use the cheap plated(or cast for that matter) 9mm bullets as youll be exceeding 1800fps with even the 147s probably. Subsonic wise youre not beating the blackout as the outlaw state bullets are 247gr and supersonic wise while youre gaining velocity over the blackout, the bullet designs in this bore diameter will bleed off that speed real quick. If decently priced 6.8 brass wasn't so damn hard to find it might be a bit more viable for mass consumption. If I want a subsonic hammer I can grab a 458 socom slinging 600gr flat noses, if I want a badass supersonic round I can grab a 6.8, if I want something that does both pretty well I can grab a blackout. What am I missing?

First of all let me begin by saying this is something that fits the criteria I laid out for what I would want in a cartridge that can conform to multiple roles. It fits into a lot of different scenarios easily with a vast variety of different available projectiles.

After having a 6.8 myself & shooting every ar15 caliber I could get my hands on I began researching what others were doing & what their experiences were with various other cartridges & calibers. I did so in order to get an idea of what, in regards to me & my criteria, would be a best possible choice. The objectivenes of that search is laid out in the 4 criteria in my original post. I certainly acknowledged that the attainable velocities of lighter 9mm offerings is going to be an area of R&D. But starting with too much velocity & having to find a way of cutting it is better in my mindvs that of not enough velocity to begin with.

For most 9mm 1200-14000fps is the speed limit. I have my work cut out for me in this regard but all I can do is give it a try.

To begin with a 300blk seemed a viable choice. That is until I dove into it indepthly to find a large lacking in the variety of low velocity projectiles in an affordable price range for large quantity reloading. The existence or a few off label offerings in 308 a cheap & easily obtainable projectile does not make.

Prior to my inkling for a 300blk I was pondering a 9mm AR or a 10mm mag/ 40s&w. While I reload both of these rounds it did not meet my criteria of a 150-200yrd capable hunting option. Next I pondered the 9x23 & 9x25 dillon. Those offered better performance but brass availability & the fact I was looking at a custom built AR with mag adapters & a very specific magazine anyway led me ask myself what could I build that would give me the power capability to fill that hunting role but follow along the lines of parts interchangeability of the 300blk.

I did not own a 556 so once looking at the 300blk I kept coming back to the fact I already had everything in 6.8. Bolts, mags, brass you name it. So seeing the potential of a superior cartridge already in - hand,  I couldn't see the point of downsizing to the 223 brass & then having to deal with the limitation of availability in regards to offering relatively inexpensive & readily available projectiles. Seeing how cheap 9mm was to reload had me hankering for something to really utilize that bullet.

Manufacturers & varieties abound for 35/ 38 caliber.  All are relatively inexpensive & readily available compared to 308 & 338 offerings. Looking to utilize that market of availability, and after considering the 10mm brasses real availabilty issues, led me to go back to my idea of using a 6.8 case to run those multitude of offerings. So then began the endeavor of building this cartridge.

On paper it can outperform 300blk in every aspect. Case capacity,  projectile offerings & availability, energy transfer & so on. With roughly 30% more case capacity it can achieve velocities the 223 cases can not in 308 offerings.

Even when bridled to sub-sonic velocities the 25% more surface area of a 35 caliber will deliver more energy than a 308.

In the hunting role I found the 200yrd limit to be a viable expectation & in this range my cat will hold its own vs a 300blk. I understand the slight balistic advantage of the 308 offerings. But when the yardage is considered as a relative maximum for 300blk those slight advantages do not outweigh the gain in velocity. From what I have seen from 125 -150grn loads in 300blk, a 180grner out of this will be equal energy with a very minor amount of drop at the itended range of use.

In regards to the other offerings of 458 & 50 caliber,  they did not fit my criteria for an inexpensive range toy by any stretch of the imagination. So those were really not a viable option.

6.8 brass availability is not that bad if you know where to look. I see it at Cabellas & other large name stores. It can be had directly from LWRCI & Wilson Combat. In my looking I procured a line on brass that, even from a manufacturing perspective for this concept in the conceivable quantities I could possible sell, would last several years.

In closing, I guess I want to essentially be able to load a huge variety of bullets for a very wide range of applications and also be able to go to the range & shoot for less than the cost of factory loaded 556 or hand loaded 300blk.

Will this be ideal for everyone? Perhaps not. But the advantages in the criteria I laid out are clear & undeniably evident. Now if I can get it to work in the aspect of a reliable feeding cartridge design is the primary task at hand. I feel I can make it work & I am never afraid of a challenge.

There are others that felt an improvement to the 300blk was needed otherwise they would not have developed new cartridges & loads. Was it Wilson that has developed a new cat recently to perform better?

There is even the 6.8blk that kicks 300blk in the groin but not to many people have ever heard of it, but it is available.

We all have our own ideas on things & we try the best we can to see our ideas come to fruition. I am no different in this respect. I just want to be able to offer an option for individuals who are looking for the same things I am looking for in a multi role cartridge.

You bring up a good point about the 358 grooving. I am really torn on this. I really feel two individual offerings would be best but if a 357 rifling could be made to work in th interim then I may go that route.

The issue I see between trying to have a one size fits all offering is the distinct fact that shorter & lighter 9mm/357's in a shorter barrel application are going to require very different rifling compared to long heavy 358's.

All this will have to be hammered out in R&D & for me that is the fun part.

I have to determine the more important focuses, relative to the objectives, in where to spend my initial time in R&D.

Playing devil's advocate here, so don't take offense.  What is the neck length on that, ½ caliber max?  I have a concern about the neck being so short that it will not hold the bullet strongly enough especially during the cycling through an autoloader.  Even a strong crimp will not make up for poor neck tension.  The wildcatters rule of thumb is a neck length equal to the caliber, or a half inch long neck for a .50 caliber, a .338 long neck for a .338 caliber…
That neck looks very short and while it would likely work fine in a bolt gun or single shot, I have a concern that the bullets might be bumped back into the case during the loading process.  With longer bullets, such as 225 gr. sub-sonics, I can envision the bullets getting tweaked in the case during feeding and not resting in the chambers square and that causing an accuracy problem.
Plus, a twist that is fast enough to stabilize the long subsonic bullets might give accuracy problems with handgun bullets.
I know, that's what R&D is for but these were a few of the issues that Marty had to deal with when he did the .338 Spectre.  He went with a 1:6.5 twist to stabilize the long 300 gr. bullets and the accuracy is just fine with the shorter 165, but they are still relatively long bullets compared to a .357 magnum bullet or 9mm bullet.
Or did I miss something and this round is only intended for use with handgun type bullets?  The shorter neck would be more in line with short handgun bullets than longer rifle bullets if they will just stay in place during feeding.
I am anxious to see how this round flies because I like the concept.  The more wildcatters the better.

No problem it fits your needs. Thats all that matters. If you can get one chamber to work I think youll have a lot better luck.

I appreciate the response and sometimes looking at things objectively makes you question aspects of a design in certain qualitative and quantitative perspectives.

The neck length is not quite half of the diameter. Close, but not quite. This was not an area of the cartridge that was my idea per say. It was Harrison at ARP that gave me the specification and said to try it there & see where it goes. The word used to me was "Perfect", so I wasn't going to question those with much more knowledge and experience than myself. Both knew the intended applications of longer projectiles & that is actualy what the first chamber is going to be based on. I will deffinaitely evaluate any movement of the bullet in the case once I have a barrel to test feeding.

Most 338's I have looked at are quite a bit longer for a given bullet mass when compared to a 35cal. This shows in their much higher BC. This would deffinately pose an issue in my mind for such a short neck. Now the 200-250grn RN subsonic loaded bullets will be seated back to the 1.75-1.8" range so the bullet will be held  closer to the o-give. For supersonic loads the 180grns, such as an interlock, will be the heaviest I would recomend loading out to 2.0". I did give the first chamber enough lead to accomodate a 200grn RN & a 250grn ballistic tip at that COAL. A 250grn RN, however, would need to be loaded to a slightly shorter COAL.

The twist rate is deffinaitely a concern for me. I have available to me any rate from 1:10 on up. I am starting with 1:14 & will see where that lands me. Mike at MGP has found 1:20 works best for his 200grn FTX's but he is running a bit more velocity in that range of bullet than I will see due to a slightly larger case capacity & longer barrels compared to what I will be using. I have to start somewhere and atleast in this range I have a basis for comparison when starting off with a shorter barrel than what is offered in the 35MGP. If I can find a happy load in this twist rate/ barrel length, I can then move up or down from there, and evaluate it with different loads/ projectiles. It will certainly be a process of elimination but more shooting is always fun!




I see two main users of this cat. The hunter who either wants to shoot a lot or doesn't and the user using it for PD & CQB & plinking that will never hunt.

For the hunting role having one barrel for longer range work & one for shorter range use would be no biggy. The hunter could have two barrels and swap out the long range one for hunting season and then go use the plinker barrel the rest of the year. I personaly wouldn't have a problem having two distinct uppers myself.

For the non-hunter, running one specific barreled upper chambered for a given range of loads should be just fine.

Thanks again both of you guys for chiming in! I appreciate the info & support.

One more thing I want to mention.  The .32 NAA handgun round shares a very short neck with the .35KLR.  When I ordered my first 4 boxes of Cor-Bon ammo for the .32 NAA, when they arrived I noticed I could spin the bullets in the case by hand.  The heavy crimp kept the bullets from being pulled out, but by golly you could spin them with your fingers.
Of course Cor-Bon replaced the ammo immediately but when I started loading I ran into the same thing.  A tiny bit of crimp was fine, but if one applied a heavier crimp it caused all neck tension to be lost.  I assume it caused the neck to bulge away from the bullet and with that short neck, the bulge was enough to lose all bullet tension.
The .32 NAA is of course a tiny little bullet, only 60 gr., formed from the .380 ACP, but when you start to reload for it, the experience I had with the .32 NAA might be something you want to keep in mind.  I would highly recommend a Lee Factory Crimp Die if Lee ever opens up their custom shop again for more orders.  That die would prevent you from applying too heavy a roll crimp and causing the loose necks like CB and I had with the .32 NAA.

Thanks for the info.

I am going to try to run this with no crimp. If I have to I will, but it is my goal to not use it.

I use a Lee factory crimper on my pistol cartridges. They work well for me so I am with you on that.

Nice take on the 9 x 39 and 9 Grom from the ComBloc.  My 358 CQB was just about the same, but 30 Rem brass all but disappeared back then (turns out it was being bought up by 6.8 SPC development team.... ).  You could look at the 10mm Mag brass as well if needed.  Happy to offer any insight where I can.  Some quick thoughts

- you will most likely need faster twist to get stable subsonics of 250 or above.  Note that .30 cal 240 gr SMK requires 1 in 8 and .338 cal 300 SMK requires 1 in 6.5.  Your 1 in 20 will not be enough I suspect.  If you intend to use 9mm suppressors, all the more so, or baffle strikes are possible.  PacNor can make ANY twist you want, you just have to pay for the tooling, but once made, it is available.  Also, it will be a fight then between the ideal twist for the pistol bullets and the rifle bullets - the faster twist may give poor accuracy with the pistol bullets (not sure why, but pistol caliber carbines end up using a faster twist to get the best accuracy)

- watch how deep you seat those long heavy ones.  ON PAPER you can seat them deep, but once you add powder, while theoretically you can fit it in the case, you have to keep in mind that it does not flow like water once that long tail starts diving into the case.  It has to seat AROUND the base of the bullet and that can be a challenge for both loading and ignition....

- if you decide to seat the heavier ones out longer (due to the above reason), then you might run into issues with finding a throat that can deal with both the short stubby pistol bullets and the long rifle bullets.  The shorties might end up jumping too far to offer good accuracy

- feeding - you will want to make a single ramp as found on the 450, 458 and 50 - I use them in my 338 Spectre and it solves all the feeding issues.

- set back - as BigBore noted, with the short neck and the short bullets, be careful regarding set back.  I would make a good number of dummy rounds with all the bullets you intend to run and cycle them by hand, from lock back and any other bolt position, mix and match projos in mags, etc until your hands are blistered and the rims are dinged up badly.  Then look at the any and all FTF, FTE, etc and look at ANY indication of set back.  Especially note any rounds that may have feed "sluggish" and look at those at extraction to see if there is any evidence of set back or any nicks on the bullet (suggesting it hit the chamber mouth at feeding).

Good luck, safe shooting and keep us posted!

BTW - the really short barrels with the heavy bullets will actually be one of the more "popular" options once you have this up and going, as it represents a particular user group that is typically more interested in this type caliber.  That said, I think with the short 9mm bullets this would make for a mean M1 Carbine conversion.... just needs the right mags...

Hey thanks Marty!

I agree with you on many aspects you brought up.

Brass is coming back strong from SSA/Nosler & Federal. Hornady still seems to be a bit slow from what I have been able to find. Rem large primer has been consistently found in small quantities.

Twist Rate: I did not have plans to run 1/20 right away. That is what Mike has found the FTX likes in his 35MGP. He is getting sub- half MOA so I think he has that dialed in. He said faster was all over the place.

Set - back will be kept to a minimum due to the issues you bring up. Powder type plays a big part here for sure.

I think H & I came up with a happy medium so far for free bore that will work well with full length loaded 140-180grn pistol & ballistics & slightly set - back 200 - 250grns balistics. The heavier round noses should be the better bet for subs, with the free bore spec now, hopefully without stuffing too much in the case. With the free - bore now they would only be loaded in ~ .3 or so. I will have to see where velocity lands for various loads & barrel length.

The short barrel sub combos are the whole reason I started this because it is what I want but with a lot of projectile options...

Quote:
For most 9mm 1200-14000fps is the speed limit. I have my work cut out for me in this regard but all I can do is give it a try.  So basically you've lost the option to use this class of bullet? Thus reducing  you variety you desired

To begin with a 300blk seemed a viable choice. That is until I dove into it indepthly to find a large lacking in the variety of low velocity projectiles in an affordable price range for large quantity reloading. The existence or a few off label offerings in 308 a cheap & easily obtainable projectile does not make.   Only if you limit youself to factory bought bullets! With cast bullets you have a great number of options. I haven't seen any increase in the avaiablity to get factory bullets -really just the opposite, an way more exspensive when you do find them.

Prior to my inkling for a 300blk I was pondering a 9mm AR or a 10mm mag/ 40s&w. While I reload both of these rounds it did not meet my criteria of a 150-200yrd capable hunting option. My 300 blk is more then capable of taking medium game out to past 200 yards Next I pondered the 9x23 & 9x25 dillon. Those offered better performance but brass availability & the fact I was looking at a custom built AR with mag adapters & a very specific magazine anyway led me ask myself what could I build that would give me the power capability to fill that hunting role but follow along the lines of parts interchangeability of the 300blk.

I did not own a 556 so once looking at the 300blk I kept coming back to the fact I already had everything in 6.8. Bolts, mags, brass you name it. So seeing the potential of a superior cartridge already in - hand, I couldn't see the point of downsizing to the 223 brass & then having to deal with the limitation of availability in regards to offering relatively inexpensive & readily available projectiles. Seeing how cheap 9mm was to reload had me hankering for something to really utilize that bullet. But you've already ruled out using using 9mm projo's do to velocity limts

Manufacturers & varieties abound for 35/ 38 caliber. All are relatively inexpensive & readily available compared to 308 & 338 offerings. Looking to utilize that market of availability, and after considering the 10mm brasses real availabilty issues, led me to go back to my idea of using a 6.8 case to run those multitude of offerings. So then began the endeavor of building this cartridge.

On paper it can outperform 300blk in every aspect. Case capacity, projectile offerings & availability, energy transfer & so on. With roughly 30% more case capacity it can achieve velocities the 223 cases can not in 308 offerings. But you have forgot that those fat ,blunt 35 caliber bullets loose velocity/energy faster

Even when bridled to sub-sonic velocities the 25% more surface area of a 35 caliber will deliver more energy than a 308.

In the hunting role I found the 200yrd limit to be a viable expectation & in this range my cat will hold its own vs a 300blk. I understand the slight balistic advantage of the 308 offerings. But when the yardage is considered as a relative maximum for 300blk those slight advantages do not outweigh the gain in velocity. From what I have seen from 125 -150grn loads in 300blk, a 180grner out of this will be equal energy with a very minor amount of drop at the itended range of use.

In regards to the other offerings of 458 & 50 caliber, they did not fit my criteria for an inexpensive range toy by any stretch of the imagination. So those were really not a viable option.

6.8 brass availability is not that bad if you know where to look. I see it at Cabellas & other large name stores. It can be had directly from LWRCI & Wilson Combat. In my looking I procured a line on brass that, even from a manufacturing perspective for this concept in the conceivable quantities I could possible sell, would last several years. But no where near as available as .223/5,56mm brass an still way more exspensive

In closing, I guess I want to essentially be able to load a huge variety of bullets for a very wide range of applications and also be able to go to the range & shoot for less than the cost of factory loaded 556 or hand loaded 300blk. can you beat $.10-.15 per round

Will this be ideal for everyone? Perhaps not. But the advantages in the criteria I laid out are clear & undeniably evident. Now if I can get it to work in the aspect of a reliable feeding cartridge design is the primary task at hand. I feel I can make it work & I am never afraid of a challenge. Not until we get the real numbers from a operational rifle /rounds down range  I wish you luck in your endevor!

There are others that felt an improvement to the 300blk was needed otherwise they would not have developed new cartridges & loads. Was it Wilson that has developed a new cat recently to perform better?

There is even the 6.8blk that kicks 300blk in the groin but not to many people have ever heard of it, but it is available. Have a lnk to anything on this -first I've heard of it?
We all have our own ideas on things & we try the best we can to see our ideas come to fruition. I am no different in this respect. I just want to be able to offer an option for individuals who are looking for the same things I am looking for in a multi role cartridge.


The other problems I see with your mock up cart. No crimp - those fat bullets will not feed unless you mod/design a new feed ramp to be used IE another part that most be swapped. And M4 style will never work!  I see bullets getting stuffed back into the case in your future.

And  I for one have zero problems getting ammo for my 300 Blk, I reload, cast so as long as I can get powder and primers I'll always be able to shoot as much as I want at pennies per round.  Good luck in your quest .

Well, I run non crimps in my rifle loads now with no issues. So maybe some of us are a lot better at getting neck tension right than others.

Yup, a single feed extension INCLUDED & pre assembled on the barrel may be needed & would still be just a barrel swap... so I fail to see the point you tried to make.

Really? Show me this magical pennies a round factory loaded 300blk ammo.. I see well over a $1.00/ rnd as the norm. $30/ 20rnd boxes are much the norm at the average chain stores. & again, your failed comparison of trying to say "I can cast my own so that is going to be cheaper than what anyone using your cat can do" is a real weak argument. Anyone can cast ANY caliber, and many do cast 35 also, I just choose not to. I don't have that much time to waste. Perhaps you do. But many of us do not. I prefer to open a box & get to loading. I have a job, a wife, kids & my time is more valuable than casting bullets to save a few cents, or argue about it on the internet.

You don't want to try my Cat. I get it. Nothing I can do about it besides saying have fun doing what your doing. I'm glad it's what you want to do.

Me, I am going to try new things & have fun doing what I'm doing.

Now some technical data:

Using some data from HERE for Hornady 150SST's we see the author saw 1822fps for an accurate load.

So lets look at those numbers vs my estimates. & before you say I won't be able to see even 2100fps the 35MGP is seeing over 2100fps with 200grn FTX's. My case capacity is a few grns les than his loaded out. 2100 is a hopefull estimate for 180grners from my cat.. Here is how it may very well compare... even if I match the 1800 fps of a 150grn out of a 300blk with 180's I will be happy. I understand this is not the max for this round but it is accurate. I have a lot of powders to try & am hopefully I will find one that is just right for hittng my goals.

With a BC of .415 here is how that breaks down accoriding to Hornady's very own Ballistic calculator. Run it yourself with 2.0" sight height, 100yrd zero.

Here is the load ballistics @ 1822 fps


Let's say you or someone else wants 100 fps better...



Let's say the 35KLR only muster 2100 fps out of a 14.5" barrel. Here is how that would look.



Now let's put the icing on the cake & say I am right & it will hit 2200fps...



I think the actual data will speak for itself...

At the very least at 200yds, which is where I have drawn the line at the begining of this thread, for an accurate load, the 180 grn out of a 35KLR should exceed the 150SST out of a 300BLK by 100ft/lb of torque. @ 300yds the 35KLR will have 13ft/lbs of torque less.

At the estimated best over this load data of Hornady 150's the 35 KLR will have 283ft/lb more torque @ 200yds. @ 300yds it will posses 127ft/lb of torque more

This is why I am doing this as I believe it will perform as I suspect. I will give it my best & see where it ends up when the powder smoke clears.

The .30 x 6.8 round that I am most familiar with is the .30 HRT, another Teppo Jutsu creation.  A 6.8 case opened up to .30 cal, cut back some and sized in a .30 Herrett die.  Pure wildcat but it kicks sand all over the .30 BO and within the .308 caliber class, it is what the .300 BO want so be when it grows up, unless it really wants to grow up then it wants to be a .338 Spectre.
The HRT bests the BO by between 200 and 400 fps with light bullets and equals the BO with subsonics.  I say equals because pushing a heavy over the speed of sound is self defeating, but the HRT can do it.

Anyway, I think it is wise for GTFoxy to try this round out.  You can make all the arguments in the world for something but until it is actually tried, it is just an exercise in mental masterbation.  I have found that many times, all the crap you print out with QL and any other ballistic calculator can be pie in the sky and only real testing will get you the truth on what a round can do.  My (Marty's creation) .470 Rhino cannot do what QL said it would do, not safely anyway.  Rifling twist calculators are another thing we use that often proves not worth the time it takes to use it once testing begins.  Too many times the real world just will not mesh with the hypothetical world, no matter how much we want it too.  Sometimes though, it is better.  My .358 HDH does BETTER than what it was predicted to do by QL.  Not by much, but better, and I'll take that.  Unless someone is willing to actually try out something then we would never get any new rounds.  I hope GTFoxy finds the round to be all he hopes it to be.  There is no greater satisfaction that to create something that is totally your creation, even if it is a money pit.  And so long as the developer is happy with it, that's all that matters.

Thanks man! I am glad to see you understand my motives here in at the very least trying it & seeing what it can do.

It may do better or may do worse. Powder/ bullets/ barrels all have an influence on the end product.

Many people forget that until the 300 whisper was developed it didn't exist & if no whisper then there would be no 300blk. We all know the real history there BTW...

I would really like to add more case volume to this but the way I want to make the brass & try to get the o - give right to the ribs in the mags to prevent modifications I am right to the limit. We all have to work within the design criteria & then do our best to find the limits of various combinations.

Thanks for the support!

The MGP will be seeing some 9mm testing & I can't wait to see how it works for him. If they will stay together out of a 35MGP I am sure I will have an easier time getting them to hold together.

Wildcats are like a box of chocolates... you never know what you're gonna' get...

Looks like you're on your way and that the R&D has merit.  I think the projected numbers look promising, and once you get some lead downrange we'll see what it's capable of.  Doesn't seem to me like you're marketing it to replace the 300BLK entirely, so not sure where all that came from.  It might be an nice alternative/improvement, though!

The case has been changed slightly & is now a bit longer for more bullet support &b case capacity with some projos.

I don't think "Replacement" of the 300blk is possible certainly not my intention. As such, I simply said I designed it to exceed its performance while maintaining it's desirable characteristics of interchangeability to its host cartridge.

I personally like the 300 whisper/ blk & find it is a nice cat.

With case mods, as big bore so eloquently put it,  some mental masterbation in the form of QL has been done.

Interestingly enough with a 6" barrel you mentioned, QL is showing ~1,800fps with a 180grn interlock in a stout load, but not unsafe. A speer hot-core should be comparable.

How does just above supersonic @ 2" of barrel length &, @ 3" of barrel ~1,500fps sound?

Where we at with this thing?!!?!?  I wanna update.

Still gathering components & waiting on reamers. I'll get the trimmer lined up yet this week.

Interesting, kinda reminds me of 338 Spectre.

I think we discussed the Spectre earlier.  The big advantage the KLR has over the Spectre is bullet selection.  No, not rifle bullets, but handgun bullets.  I am quite certain one cannot find 110 gr. bullets in .338, but in .357 they are a dime a dozen, so to speak.  If they will hold together during flight they will offer an extremely explosive round with minimal risk of over penetration or ricochet.  Or you can shoot 250 gr Woodleighs should the mood strike.

Reserved.

Sounds neat, the "neck" on the cartridge worries me a bit. I like to have a neck that holds at least a calibers length, but if it works well go for it. Good luck, it would be nice to see another caliber out there :)

If you can get 35 Remington velocity out of a little cartridge with a Remington core loct 200grn  I could be in for one of these. Holy deer slayer!

AL

I'm hoping it will be enough for what I want it to do. Have to test it & see.




The cartridge has been revised. It should have plenty of neck now.

I think it's interesting to say the least, however it don't see this catching on, feed ramps with round nosed bullets, 35cal cans? Which are rare for rifle pressures. Just the fact that 5.56 cases are so plentiful and cut down easily and there are so many varieties of 30 cal cartridges to select from, 300 blk is already SAAMI spec'ed and just about every manufacturer offers a 300blk option

The same could be said in regards to a 458 socom. It will be SAAMI soon.

I will see how it feeds but to be honest I'm not too worried.

Everything has to start somewhere. It only took the 300 whisper/BLK 20 yrs to get where it is now. Even longer if you consider the original 221-30 fireball...

I addressed the brass side of it already.

Performance draws people regardless of some inherent variances. I like the idea of a 35cal in a few different case sizes. The 35MGP & the KLR should make fine bed-fellows.. It is my aspiration to make high-power 35cal cans a reality & available for this. I think I mentioned that also.

I agree, but the hurdles are mountains at this point. Good luck.


ETA,

Why not look into creating some subsonic 6.8 that runs reliably. The BC on .270 cal or 30 cal bullets is going to be better than those round nose 9mm bullets anyway.

Reserved

Bump.

Bison has a sub barrel that is working good with subs & 220grns & IIRC there are works for one more heavy.

The .277 caliber pills certainly have a warm place in my heart since I have been a 270 user since I was a kid.

I think people are focusing more on the 355/356 projectiles a tad much. Those are not on the top of the list, yet simply an "Option" for a loader in say times when specific bullets may not be as readily available, or if they just have them to use, or they may just like using them. The lower end of the spectrum in masses for these is not my primary concern. I will test them but they are not to be the mainstay of this cat. Plenty of 35cal pistol & rifle pills out there to choose from, but simply having that option is nice for cheap plinking, IMO.

In terms of pistol projo's, I see the 140grn & up being the sweet spot for pistol hunting & heavier for sub use. There is currently 325grn casts in the works for this from a private manufacturer. Also, a certain manufacturer is being consulted on a high BC 130-150grn pill, so we will see how that pans out.

Performance data is not far off at this point.

Following this with some interest as I like the .35 rifle calibers.

Though I don't expect it to match the performance of my 350 Rem Mag,

Those Rem. Mags were pretty stout.

What is the host rifle for that beast?

Barrels are being made... test numbers hopefully soon.

Bump