Originally Posted By Bearbait1: Mic McPhereson has written extensively about this powder ignition situation in various articles in the Varmint Hunter magazine over the years.  He has gone as far as designing his own type of elliptical shouldered cartridge line, to deal with it.  His testing protocals and results have been enlightening, to say the least. Craig

The inventors of the PPC cartridges extensively studied the primer flash cone and designed their case around it.  Their cases are among some of the most efficient around.  It's not all just about shoulder, it's about the total of all the aspects of the case.

Originally Posted By 762x40mm: Originally Posted By J-A-R: I have heard of this myself with the 30 carbine performing better than it should with its limited case volume. So I can see how it would also apply to the 7.62x40mm with its case design. Joe Funny you mention the 30 carbine....I used the analogy of a 30 carbine on steroids a few days ago in a discussion about the 40.....I have been suprised that several of the tried and true 30 carbine bullets cycle in the 40....the sierra 110 HP is one of my favorites....should make one hell of a varmint control load..... 40

I was thinking the same thing when I first read your post 30 carbine magnum or 30 carbine on steroids. About 3 weeks ago I sent an email to Olympic Arms about their 30 carbine conversion for the AR but they have no plans to produce it again. So your coming out with the 7.62x40 caught my eye. This looks to be a fun build project so might as well jump in and give it a try.

Joe

Originally Posted By JFA: Don't be so surprised as to what load will function an AR action.  I've told you I shoot cast out of three AR's.   Part of my procedure for finding a good load is starting out very low in velocity and working up till I get the velocity and grouping I want.  I've cycled AR's with very very anemic cast loads.  On another note the French MAS 49/56, which has a DI gas system also cycles on pretty much anemic loads.  On the other hand my SKS doesn't.  I've come to the conclusion that it has something to do about the DI gas system.  It doesn't take a lot of gas to cycle it.

I would like to get into boolit making.....a neighbor was into casting bullets and jig heads, always intrigued me.....I just don't have the room right now in my shop....It looks like it would be a learned art, a little different from the reloading that I am acustomed.....just from looking at some of the boolit forums many of the myths of the "crud" associated with casts have been debunked.....

40

Originally Posted By JFA: The inventors of the PPC cartridges extensively studied the primer flash cone and designed their case around it.  Their cases are among some of the most efficient around.  It's not all just about shoulder, it's about the total of all the aspects of the case.

I had a conversation with a retired NASA engineer a couple years ago about model rockets....he mentioned that the optimum combustion angle of the de Laval nozzle or convergent-divergent nozzle is 30 degrees.....I kinda smiled and said "it works pretty good in rifle cartridges too"....this spawned a whole new conversation.....

40

This has been one of the most interesting discussions I have read in a while.And really not what I expected when I clicked on the "7.62x40".It's fascinating to see how this cartridge of yours works.Looking forward to any caliber variations you might do.


         

Originally Posted By gdblair: This has been one of the most interesting discussions I have read in a while.And really not what I expected when I clicked on the "7.62x40".It's fascinating to see how this cartridge of yours works.Looking forward to any caliber variations you might do.

I'm just not sure if the other caliber variations will work as well from a pressure drop stand point....someone help me out here......I think the smaller bores may drop pressure slower, would probably give a "longer" pressure curve, may work better in a rifle length gas system.....the rifle length gas system has been a little bit of a ...."challenge".....to get to work with the 40, but when I did get it to work I knew that I was robbing the absolute least "gas" from the system to get it to cycle....and runs very clean.........I have a "slim" 40 in the works but only time will tell.....

40

Have you considered a non-direct impingement system.They seem to be less finicky on pressure.

ETA- you could run a large port with a reg di gas block and have an adjustable tube running to a modified piston type gas block.

Originally Posted By gdblair: Have you considered a non-direct impingement system.They seem to be less finicky on pressure. ETA- you could run a large port with a reg di gas block and have an adjustable tube running to a modified piston type gas block.

I just recently made two gas valves for two of my AR's.  Now I can dial in what I want. Like I was telling 7.62x40 at how amazed he would be at what anemic cast loads function my rifles, I was shocked how far I had to turned the gas valve down to throttle the gas where I wanted it.

Not that I'm a big fan of the gas piston, but it does seem to be more fine tunable then the DI system.  All the DI systems I've fired have pretty violent case extraction except for the AR15. Those Egyptian Hakims will kill you with the brass.  Worse piston system I've see for violent case extraction was my best friends Valmet in 223.  Now that thing would definitely hurt you with a thrown case.

Originally Posted By JFA: Originally Posted By gdblair: Have you considered a non-direct impingement system.They seem to be less finicky on pressure. ETA- you could run a large port with a reg di gas block and have an adjustable tube running to a modified piston type gas block. I just recently made two gas valves for two of my AR's.  Now I can dial in what I want. Like I was telling 7.62x40 at how amazed he would be at what anemic cast loads function my rifles, I was shocked how far I had to turned the gas valve down to throttle the gas where I wanted it. Not that I'm a big fan of the gas piston, but it does seem to be more fine tunable then the DI system.  All the DI systems I've fired have pretty violent case extraction except for the AR15. Those Egyptian Hakims will kill you with the brass.  Worse piston system I've see for violent case extraction was my best friends Valmet in 223.  Now that thing would definitely hurt you with a thrown case.

Funny that you should mention the Valmet in 223 because I was thinking of doing my 6.8x43/17rem on an AK action.I might have to run my gas mod on it.

I have owned several weapons with "operating rods" and "DI"......I have been intrigued by the adaptation of the operating rod to the AR platform since it started mainstreaming to the public.......

I won't name any names but I called one very well known company about building a operating rod 300 whisper AR....the response I got was akin to 'hello...collect call from Mars anybody want to talk to this dumbass, no, call back when you want to build a real rifle...goodbye'.....they have probably missed out on about 10K business from  me with that one respofnse.....I called another and asked the same and you would of thought I called and told him his adjustable block DI system was crap and I wanted to build something better.....after we both calmed down a little I ended up having a pretty good working relationship with this person...

I only say all of this to affirm that I believe both systems have merrit and I have pursued an operating rod AR but have yet to build one....a few years have passed and manufactures of the operating rod systems may be a little more receptive to questions concerning wild-cat cartridges....may have to put one back on the list of things to do....

40

Originally Posted By 762x40mm: I have owned several weapons with "operating rods" and "DI"......I have been intrigued by the adaptation of the operating rod to the AR platform since it started mainstreaming to the public....... I won't name any names but I called one very well known company about building a operating rod 300 whisper AR....the response I got was akin to 'hello...collect call from Mars anybody want to talk to this dumbass, no, call back when you want to build a real rifle...goodbye'.....they have probably missed out on about 10K business from  me with that one respofnse.....I called another and asked the same and you would of thought I called and told him his adjustable block DI system was crap and I wanted to build something better.....after we both calmed down a little I ended up having a pretty good working relationship with this person... I only say all of this to affirm that I believe both systems have merrit and I have pursued an operating rod AR but have yet to build one....a few years have passed and manufactures of the operating rod systems may be a little more receptive to questions concerning wild-cat cartridges....may have to put one back on the list of things to do.... 40

......yeah, but I wonder if the current piston rod fad will fade away.  You see this has been an on going thing since the military first took possession of the M16.  The Army say they'd like a piston system. Colt made one, the Army rejected it.  About one of the first commercial systems was the Rhino.  It didn't fare too well and time went by till present.  We'll just have to wait see.

Originally Posted By JFA: ......yeah, but I wonder if the current piston rod fad will fade away.  You see this has been an on going thing since the military first took possession of the M16.  The Army say they'd like a piston system. Colt made one, the Army rejected it.  About one of the first commercial systems was the Rhino.  It didn't fare too well and time went by till present.  We'll just have to wait see.

I agree....I usually wait until I get to wrap my hands around something and try it myself to see it if fits my needs, but I really havn't had any mechanical issues with the DI system for the last twenty or so years.....although the 40 has recently opened my eyes to the use of a cartridge of this capacity with a rifle length gas system and the need for a more "efficient" (for lack of a better word) delivery of energy to the bolt carrier, DI or rod......in the rifle length gas system application...

40

Originally Posted By GlockSlap: I liked the expanding chamber concept too-but I don't know shit about building cartridges, or even reloading-but a few years ago I cooked up a few cartridges in my head, and this was one of them-after reading about the 6.8, 6.5 Grendel, etc. Someone else came up a round (can't remember the name of it) but it worked with stock magazines, maintained full 30 round capacity, would fit belt links for MG's, and required no changing of the bolt-just the barrel. I don't know what happened to it, but it seems like your cartridge is the answer if the .mil wants something that isn't going to cost a fortune. Personally, I don't think they are going to adopt a different cartridge-but this round is cool.  Is it available commerically, or reloading only?

I just saw a thread 6.8x45 kramer ucc , was that the cartridge that you were refering to?

762x40 :
Have you had any luck finding someone to make the barrels.

Joe

Originally Posted By J-A-R: 762x40 : Have you had any luck finding someone to make the barrels. Joe

Hi Joe,

I have 14 barrels lined up right now....from 16" to 20"....carbine, mid, and rifle length gas systems....sorry, no estimated time of arrival.....

I have had a few people ask me if a 40 rechambered model 1 300-221 barrel will work......yes they will, I have rechambered three of them so far.....I think the 1:8 twist is more suitable for the sub-sonics though.....the model 1 has a bigger port than what I suggest for the 40 in a carbine, so I definitely recommend an adjustable gas block....the larger port unrestricted cycles the action harder than it needs to and also robs some velocity....the guys that bought them are using them as "blasters", and they work great for an inexpensive barrel, although a 1:12 twist works much better....more velocity and your not spinning the bullets at 200,000+ rpm....

Thanks,

40

Originally Posted By 762x40mm: Originally Posted By J-A-R: 762x40 : Have you had any luck finding someone to make the barrels. Joe Hi Joe, I have 14 barrels lined up right now....from 16" to 20"....carbine, mid, and rifle length gas systems....sorry, no estimated time of arrival..... I have had a few people ask me if a 40 rechambered model 1 300-221 barrel will work......yes they will, I have rechambered three of them so far.....I think the 1:8 twist is more suitable for the sub-sonics though.....the model 1 has a bigger port than what I suggest for the 40 in a carbine, so I definitely recommend an adjustable gas block....the larger port unrestricted cycles the action harder than it needs to and also robs some velocity....the guys that bought them are using them as "blasters", and they work great for an inexpensive barrel, although a 1:12 twist works much better....more velocity and your not spinning the bullets at 200,000+ rpm.... Thanks, 40

Thats good news about the barrels, I sent you a IM about them. Sounds like things are starting to move right along.

Thanks
Joe

Originally Posted By 762x40mm: Originally Posted By JFA: ......yeah, but I wonder if the current piston rod fad will fade away.  You see this has been an on going thing since the military first took possession of the M16.  The Army say they'd like a piston system. Colt made one, the Army rejected it.  About one of the first commercial systems was the Rhino.  It didn't fare too well and time went by till present.  We'll just have to wait see. I agree....I usually wait until I get to wrap my hands around something and try it myself to see it if fits my needs, but I really havn't had any mechanical issues with the DI system for the last twenty or so years.....although the 40 has recently opened my eyes to the use of a cartridge of this capacity with a rifle length gas system and the need for a more "efficient" (for lack of a better word) delivery of energy to the bolt carrier, DI or rod......in the rifle length gas system application... 40

I know you've been bombarded with questions; but, could you explain a little more on what you mean with the rifle length gas system?

I am not about to start a piston vs. DI debate, at all; but what are you suggesting with the 7.62 x 40 by your post?

Originally Posted By ARmory04: Originally Posted By 762x40mm: Originally Posted By JFA: ......yeah, but I wonder if the current piston rod fad will fade away.  You see this has been an on going thing since the military first took possession of the M16.  The Army say they'd like a piston system. Colt made one, the Army rejected it.  About one of the first commercial systems was the Rhino.  It didn't fare too well and time went by till present.  We'll just have to wait see. I agree....I usually wait until I get to wrap my hands around something and try it myself to see it if fits my needs, but I really havn't had any mechanical issues with the DI system for the last twenty or so years.....although the 40 has recently opened my eyes to the use of a cartridge of this capacity with a rifle length gas system and the need for a more "efficient" (for lack of a better word) delivery of energy to the bolt carrier, DI or rod......in the rifle length gas system application... 40 I know you've been bombarded with questions; but, could you explain a little more on what you mean with the rifle length gas system? I am not about to start a piston vs. DI debate, at all; but what are you suggesting with the 7.62 x 40 by your post?

Sure will.  The original M16 was a full length rifle. So the gas tube length, gas port hole size, and how far up the barrel the hole was drilled was all figured to supply the correct amount of gas to the bolt/carrier.  So then they came out with the carbine with a shorter barrel. You couldn't put a rifle full length gas tube on it, nor drill the port hole out far enough to an area of lesser gas pressure in the bore.  So they made a shorter gas tube, the hole closer to the bolt/carrier group, and a smaller gas port hole.   They changed some other things on the carbine too, for example the recoil spring and buffer, along with the collapsible stock and shorter hand guards.

Originally Posted By ARmory04: Originally Posted By 762x40mm: Originally Posted By JFA: ......yeah, but I wonder if the current piston rod fad will fade away.  You see this has been an on going thing since the military first took possession of the M16.  The Army say they'd like a piston system. Colt made one, the Army rejected it.  About one of the first commercial systems was the Rhino.  It didn't fare too well and time went by till present.  We'll just have to wait see. I agree....I usually wait until I get to wrap my hands around something and try it myself to see it if fits my needs, but I really havn't had any mechanical issues with the DI system for the last twenty or so years.....although the 40 has recently opened my eyes to the use of a cartridge of this capacity with a rifle length gas system and the need for a more "efficient" (for lack of a better word) delivery of energy to the bolt carrier, DI or rod......in the rifle length gas system application... 40 I know you've been bombarded with questions; but, could you explain a little more on what you mean with the rifle length gas system? I am not about to start a piston vs. DI debate, at all; but what are you suggesting with the 7.62 x 40 by your post?

No problem....The four basic length gas systems in a AR-15 DI system are: Pistol, Carbine, Mid-Length, and Rifle...

Since the rifle length system gas port is farthest from the chamber it is subjected to the least amount or lowest point of the pressure curve......makes it the most difficult to make cycle due to receiving the least amount of "gas"....

the most direct means of getting a 20" barrel rifle length gas system 40 to run is by keeping the velocity up above 2,500 fps(keeps the pressure up) with Accurate 1680 powder (has a longer pressure curve than faster powders) and using a gas port between .106 and .110....works and cycles good....what I was illuding to is that all of the "make work" tricks are used up to get and keep the pressure high enough to make the rifle-length system work.....velocity up, slower powder, and bigger port.....you can also change to a lower tension buffer spring and lightened buffer but that defeats the "keeping everything as stock as possible" ....

I was also trying to keep out of a DI Vs Operating Rod debate....by using the term "more efficient" delivery of the gas to the bolt carrier, and could apply to either system....

for the sake of what I have tested with the 40 I'll talk about the DI......with the rifle-length DI system on the 40 it needs to operate at its most "efficient" due to the lower amount of available pressure....so how do you make it more efficient.....start at the gas port and move back.....clean drilled gas port, good port to block alignment, good block to barrel seal, good block to tube seal, good tube to gas key seal, good gas key to carrier seal, proper alignment of gas rings and carrier fit.....any leaks at these points releases pressure and makes the system less efficient....

from what I have read some of the operating rod systems do make more "efficient" use of available gas pressure, but the ones that I have looked at are set up for .223 bore rifles....the pressure curve and available pressure with the smaller bore is usually higher at the point of the rifle length gas port than what is available with the 40....so most of the rifle length operating rod systems are vent ported to operate at these pressures rather than the lower available pressure of the 40....would require something like an adjustable block or a selection of operating rod / piston vents....

Thanks,

40

Kurt,

Check your email.

762x40mm :
What are the specs. for the barrels.

1. Stainless Steel
2. Twist rate 1 in 12"
3. Barrel extension M4 cuts or standard
4. Dia. of barrel at gas block
5. Muzzle thread 5/8"x24
6. Barrel profile


Thanks
Joe

I worked up some comparitive info for another ARF member ( 320pf ) interested in making Major Power Factor using the 40 with a 16" barrel in 3 gun competition....

320pf has several 300 Whisper loads on Realoaders Nest and I used his stopping loads as a starting point for the 40....


His set-up as I understand it....

AR-15 300 Whisper 1:8 16" Noveske barrel ported in the pistol position...

19grains W296 135 Matchking = 2,237 fps

17grains H4227 155 Palma Matchking = 1,908 fps



40 Test rifle....

AR-15 300 Fireball 1:8 Olympic barrel ported in the carbine position rechambered to 7.62x40mm.....

19grains W296 135 Matchking = 2,211 fps
19.5grains W296 135 Matchking = 2,270 fps
20grains W296 135 Matchking = 2,310 fps
20.5grains W296 135 Matchking = 2,350 fps....2,371 would make Major Power Factor


17grains H4227 155 Palma Matchking = 1,915 fps
17.5grains H4227 155 Palma Matchking = 1,970 fps
18grains H4227 155 Palma Matchking = 2,010 fps
18.5grains H4227 155 Palma Matchking = 2,050 fps....2,065 would make Major Power Factor

A couple of the loads came very close ( less than 3 units ) from making Major Power Factor ( 317.75 out of 320 )....

It looks like the go-to load for an attempt at this is going to be the 155 Palma with the H4227....plenty of room in the case and pressure looks great.....will bump the load next week when I have a littlle more time.....working on a couple other projects....


The 155 Palma loaded to mag length next to our newest creation: der boomin matchking flugen launchin 7.62x63mm Unurbain Combatnotin Cartridgeshlozen.....or the 63 for short....pat. pending....can't seem to get it to fit in unmodified pmags

Originally Posted By J-A-R: 762x40mm : What are the specs. for the barrels. 1. Stainless Steel 2. Twist rate 1 in 12" 3. Barrel extension M4 cuts or standard 4. Dia. of barrel at gas block 5. Muzzle thread 5/8"x24 6. Barrel profile Thanks Joe

1. Stainless Steel.....yes
2. Twist rate 1 in 12".....yes
3. Barrel extension M4 cuts or standard......extended
4. Dia. of barrel at gas block........750"
5. Muzzle thread 5/8"x24.......yes
6. Barrel profile.......980" contour under handguard to gas block seat


thanks for the question joe.....

Unbelievably Sweeeeeeeeet........



A pistol / SBR 40 in the works.....

Ok, it looks like I will get the answer to my question about short barrel performance, without even asking.

Just when you thought the BRD was over...page 6 is mine.

This looks like a promising cartridge, sure would be nice to do something with all the extra .223 brass and extra .308 bullets.

762x40mm,

Whats the word on the dies? Time frame and cost? I was also wondering if you could post some of the loads you have worked up.  I've found a decent amount of information on th 300/221 whisper/fireball but this cartridge looks more interesting.  By the way, great work on putting all of this together.-Kag

Originally Posted By Powder_Burns: Just when you thought the BRD was over...page 6 is mine. This looks like a promising cartridge, sure would be nice to do something with all the extra .223 brass and extra .308 bullets.

Thanks for the vote of confidence.....hopefully we will be able to help you use up those extra cartridge components

Originally Posted By Kag: 762x40mm, Whats the word on the dies? Time frame and cost? I was also wondering if you could post some of the loads you have worked up.  I've found a decent amount of information on th 300/221 whisper/fireball but this cartridge looks more interesting.  By the way, great work on putting all of this together. -Kag

Spoke to the die maker yesterday....was told the die project was started and on track....usually a single set of wild-cat custom dies takes 6 to 8 weeks to make and costs around $175.00 to $200.00 dollars.....We took the bite and ordered 30 sets to get your cost down to $100.00 per set.....the delivery time on the dies is a little hard to say right now....the reamers for the dies still need to be made, packaging and labeling made, heat treating done, etc.....

Load Data: (standard disclaimer as with any wild-cat, use at own risk and work up slow)

7.62x40mm 16" 1:8 Olmypic .078 gas port carbine length gas system, fire-formed brass...

125 TNT 21.5gr H4227 = 2,230 fps
125 TNT 22.0gr H4227 = 2,350 fps
125 TNT 22.5gr H4227 = 2,440 fps
125 TNT 25.8gr 1680 = 2,430 fps
125 TNT 22gr lil-gun = 2,540 fps
125 TNT 22gr H110 = 2,480 fps
125 TNT 22gr W296 = 2,475 fps

135 SMK 19gr W296  = 2,211 fps
135 SMK 19.5gr W296 = 2,270 fps
135 SMK 20gr W296 = 2,310 fps
135 SMK 20.5gr W296 = 2,350 fps

155 SMK 17gr H4227 = 1,915 fps
155 SMK 17.5gr H4227 = 1,970 fps
155 SMK 18gr H4227 = 2,010 fps
155 SMK 18.5gr H4227 = 2,050 fps
155 SMK 18.8gr H4227 = 2,072 fps
155 SMK 19gr H4227 = 2,095 fps


My favorite loads right now are the:

125 TNT 22.5gr H4227 = 2,440 fps
135 SMK 20.5gr W296 = 2,350 fps.....going to try the 135's with the 4227 this weekend.
155 SMK 19gr H4227 = 2,095 fps.... 320  Major Power Factor with a 16" barrel.....WoooooooHoooooo

thanks for the positive feedback and hope to have a better idea on the dies in a week or so....

Thanks again,

40

Originally Posted By 762x40mm: Originally Posted By J-A-R: 762x40mm : What are the specs. for the barrels. 1. Stainless Steel 2. Twist rate 1 in 12" 3. Barrel extension M4 cuts or standard 4. Dia. of barrel at gas block 5. Muzzle thread 5/8"x24 6. Barrel profile Thanks Joe 1. Stainless Steel.....yes 2. Twist rate 1 in 12".....yes 3. Barrel extension M4 cuts or standard......extended 4. Dia. of barrel at gas block........750" 5. Muzzle thread 5/8"x24.......yes 6. Barrel profile.......980" contour under handguard to gas block seat thanks for the question joe.....

John Noveske will be making our barrels for us!!

A list of barrel combinations we are having made.....

20" SS 1:12 twist polygonal bore mid-length gas system threaded muzzle low profile gas block
20" SS 1:12 twist polygonal bore mid-length gas system crowned muzzle low profile gas block
16" SS 1:12 twist polygonal bore mid-length gas system threaded muzzle low profile gas block
16" SS 1:12 twist polygonal bore carbine length gas system threaded muzzle low profile gas block
16" SS 1:12 twist polygonal bore carbine length gas system crowned muzzle low profile gas block

Thanks,

40

762x40 :
This is the one I am interested in.
16" SS 1:12 twist polygonal bore mid-length gas system threaded muzzle low profile gas block. Tried to send you an IM but it does not show it was sent.

Thanks
Joe

762x40
How well does the mid length gas port work with the 40? From my research the 300 whisper is pretty finicky about cycling, hence pistol length systems. I think I want to use Adams Arms carbine piston system to power this 7.62x40mm I want to build.  I'm planning on shooting mainly supersonics so maybe its not big deal.hinking.gif Any thoughts from your testing.-Kag

762x40
Almost forgot.hose
-Kag

There is a fare amount of case trimming of the parent 223 case to get it ready for forming. I am sure many of you like me do not have a lathe to make quick work of this task. So I started to look for other options and came up with the Forster power case trimmer that works with a drill press. The best price I found was at Midsouth Shooters Supply. Here is a link if you want to take a look.

Midsouth Forster Link

I also ordered the collet and pilots to go with it

00070CT102   CASE TRIMMER PILOT .223  

00070CT1030 CASE TRIMMER PILOT .308

00070CT2001 CASE TRIMMER COLLET #1


Joe

Originally Posted By Kag: 762x40 How well does the mid length gas port work with the 40? From my research the 300 whisper is pretty finicky about cycling, hence pistol length systems. I think I want to use Adams Arms carbine piston system to power this 7.62x40mm I want to build. I'm planning on shooting mainly supersonics so maybe its not big deal. Any thoughts from your testing. -Kag 762x40 Almost forgot.  I would be interested in one(or more) of those Noveske barrels.  The 16" carbine or mid length with the threaded muzzle sounds great.   Did John give you any time on these.   Sometimes waiting for a Noveske can take awhile.  It's worth the wait though.  Good choice on supplier for the barrels. -Kag

The 40 produces a good bit more "gas" than the Whisper......I have a rifle length gas system that I have been able to get to cycle reliably with a little work and the right powder.....A carbine piston system will be really neat, although the carbine length DI system is a very "easy" set-up...broad powder selection (have used burn rates as fast as lil-gun down to 3031).....

Thanks for the compliment on the selection of barrel supplier.....I only took my own personal experience and satisfaction with the prototype 40 Noveske barrel and thought anyone who ended up with one for their 40 will be just as happy....John has a very quality operation from front to back, even the way their barrels are protected and wrapped for shipping speaks of quality....Did not even ask an ETA, too busy working out other details....

Thanks for the interest,

40

Originally Posted By J-A-R: There is a fare amount of case trimming of the parent 223 case to get it ready for forming. I am sure many of you like me do not have a lathe to make quick work of this task. So I started to look for other options and came up with the Forster power case trimmer that works with a drill press. The best price I found was at Midsouth Shooters Supply. Here is a link if you want to take a look. Midsouth Forster Link I also ordered the collet and pilots to go with it 00070CT102   CASE TRIMMER PILOT .223   00070CT1030 CASE TRIMMER PILOT .308 00070CT2001 CASE TRIMMER COLLET #1 Joe

Hi Joe,

Thanks for the post on the power trimmer....they can definitely speed things up....

I have been talking with a fella about cut-down or formed 40 brass delivered to your door......WoooooHooooo.....But I'll let him elaborate if he is watching....

I sent you an IM about the barrel and put your name on one.....


Thanks,

40

I'm interested in one of the 20" crowned barrels. This sounds like just the ticket for my predator gun.

Originally Posted By FALFire: I'm interested in one of the 20" crowned barrels. This sounds like just the ticket for my predator gun.

Just finished sending you an IM....thanks for the interest

40

double post, I'll put something here in a little while

height=8

Originally Posted By 762x40mm: height=8 Originally Posted By FALFire: I'm interested in one of the 20" crowned barrels. This sounds like just the ticket for my predator gun. Just finished sending you an IM....thanks for the interest 40

Got it.

That's kinda what I was expecting and the mid-length is a perfect match. Great choice on Noveske too. Looks like I'll be ordering one up real soon, just got to work out the details with my banker, she's cookin' up some grub right now so this ain't a good timeI'll be gettin' back at'cha though.

Crap it looks like I have to build another AR. 30-30 performance in a black semi auto platform? I like what I see.

Originally Posted By Powder_Burns: Crap it looks like I have to build another AR. 30-30 performance in a black semi auto platform? I like what I see.

Thanks for the comparison to a long time standing favorite like the .30-30......Will be testing more 155 loads to see how close it can come to the .30-30.....The .30-30 has a definite capacity and power advantage especially with heavier bullets.....the 40 is maybe closer in performance somewhere between the 1.6" .30 Herrett (the .30-30 wild-cat for use with 10 to 14" barrels) and the .30-30....

Going to the range today to test a couple rifles and do some load building with the 135 and 155 Matchkings.....will post the results later today

Go here http://www.accuratereloading.com/76239.html   and look at what the "old" 7.62x39 can do.  Granted this is in a bolt gun with a long barrel, but look at the heavier bullet weight velocities.   The 7.62x40 isn't the only round compared to the 30-30...the 7.62x39 had been and much earlier.

With the new "specialty" bolts out (made of new much tougher steels) the AR15 can achieve these velocities too.

Well yeah, but the 7.62x39 is a tapered case with a .310 projectile, so it doesn't do anything for me.

Originally Posted By 762x40mm: Load Data: (standard disclaimer as with any wild-cat, use at own risk and work up slow) 7.62x40mm 16" 1:8 Olmypic .078 gas port carbine length gas system, fire-formed brass... 125 TNT 21.5gr H4227 = 2,230 fps 125 TNT 22.0gr H4227 = 2,350 fps 125 TNT 22.5gr H4227 = 2,440 fps 125 TNT 25.8gr 1680 = 2,430 fps 125 TNT 22gr lil-gun = 2,540 fps 125 TNT 22gr H110 = 2,480 fps 125 TNT 22gr W296 = 2,475 fps 135 SMK 19gr W296  = 2,211 fps 135 SMK 19.5gr W296 = 2,270 fps 135 SMK 20gr W296 = 2,310 fps 135 SMK 20.5gr W296 = 2,350 fps 155 SMK 17gr H4227 = 1,915 fps 155 SMK 17.5gr H4227 = 1,970 fps 155 SMK 18gr H4227 = 2,010 fps 155 SMK 18.5gr H4227 = 2,050 fps 155 SMK 18.8gr H4227 = 2,072 fps 155 SMK 19gr H4227 = 2,095 fps My favorite loads right now are the: 125 TNT 22.5gr H4227 = 2,440 fps 135 SMK 20.5gr W296 = 2,350 fps.....going to try the 135's with the 4227 this weekend. 155 SMK 19gr H4227 = 2,095 fps.... 320  Major Power Factor with a 16" barrel.....WoooooooHoooooo thanks for the positive feedback and hope to have a better idea on the dies in a week or so.... Thanks again, 40

Back from the range.......got a few more loads to post

Load Data: (standard disclaimer as with any wild-cat, use at own risk and work up slow)

7.62x40mm 16" 1:8 Model 1 .085 gas port carbine length gas system, fire-formed brass...(note: the Model 1 barrel with the larger port produced lower velocity than the above Olympic barrel with a smaller port)

155 SMK 18.5gr H4227 = 2,048 fps
155 SMK 18.8gr H4227 = 2,057 fps
155 SMK 19gr H4227 = 2,068 fps
155 SMK 19.2gr H4227 = 2,086 fps



7.62x40mm 16" 1:8 Olmypic .078 gas port carbine length gas system, fire-formed brass...

135 SMK 19gr H4227  = 2,149 fps
135 SMK 19.5gr H4227 = 2,190 fps
135 SMK 20gr H4227 = 2,240 fps
135 SMK 20.5gr H4227 = 2,278 fps
135 SMK 21gr H4227 = 2,312 fps
135 SMK 21.5gr H4227 = 2,330 fps
135 SMK 22gr H4227 = 2,361 fps

Hope this info helps and Happy 4th

Originally Posted By JFA: Go here http://www.accuratereloading.com/76239.html   and look at what the "old" 7.62x39 can do.  Granted this is in a bolt gun with a long barrel, but look at the heavier bullet weight velocities.   The 7.62x40 isn't the only round compared to the 30-30...the 7.62x39 had been and much earlier. With the new "specialty" bolts out (made of new much tougher steels) the AR15 can achieve these velocities too.

I don't think the comparision that Powder_Burns or I made with the .30-30 was to suggest that the 40 was the only cartridge similar to it's ballistics.....I have the utmost respect for the 39 and it's capabilities....

I had looked at the accuratereloading data for the 7.62x39mm before....but come on, that thang has 10 inches more barrel and no gas system, I don't know if changing to a "specialty" bolt is going to make up for 10" more barrel....the additional barrel length alone is good for 200 to 250 fps increase.....I am in the process of building a 24" 40 bolt gun and expect a similar increase....

Thanks and have a Happy 4th

Originally Posted By JFA: With the new "specialty" bolts out (made of new much tougher steels) the AR15 can achieve these velocities too.

Are these on the market now?

Hi bfarrin1,

have you got to shoot your "project" yet?........

I apologize but I havn't been able to go by the Post Office the last couple days(working out of town) and they are closed today....so maybe Monday

Thanks,

40

Originally Posted By bfarrin1: Originally Posted By JFA: With the new "specialty" bolts out (made of new much tougher steels) the AR15 can achieve these velocities too. Are these on the market now?

Yup...this one http://www.jprifles.com/buy.php?item=JPBC-LWBA in the 5.56 size....and the current AA 6.5 Grendel bolt in 6.5/7.62x39 size is made of the same steel.   By the way the JP one can be opened up too if done right. MGI I believe soon to release.

height=8

Originally Posted By JFA: Go here http://www.accuratereloading.com/76239.html   and look at what the "old" 7.62x39 can do.  Granted this is in a bolt gun with a long barrel, but look at the heavier bullet weight velocities.   The 7.62x40 isn't the only round compared to the 30-30...the 7.62x39 had been and much earlier. With the new "specialty" bolts out (made of new much tougher steels) the AR15 can achieve these velocities too.

havehinking.gif but this thread is focused on the 7.62x40mm.  

Originally Posted By Kag: Originally Posted By JFA: Go here http://www.accuratereloading.com/76239.html   and look at what the "old" 7.62x39 can do.  Granted this is in a bolt gun with a long barrel, but look at the heavier bullet weight velocities.   The 7.62x40 isn't the only round compared to the 30-30...the 7.62x39 had been and much earlier. With the new "specialty" bolts out (made of new much tougher steels) the AR15 can achieve these velocities too. Id have to agree with PowderBurns.  If you can get a 7.62x39Russian to fit in Pmags, feed reliably, and shoot sub moa out of a slightly modified(barrel only) AR15 let me know.  There are close to two pages of complaints and comparisons to the 7.62x39Russ in this post and i feel that is pretty rude.  If you favor the 7.62x39 Russ then thats fine, but this thread is focused on the 7.62x40mm.

I built a 7.62x39 and used a Wilson heavy profile 20 inch barrel and it shoots a cast 155 gr bullet at 2000 fps in a .437 inch five shot group at 100 yards and feeds very reliable out of my 6.5 Grendel magazines.

Didn't say I favored the 7.62x39 just saying the 7.62x40 isn't anything new and isn't any better or worse then .62x39.  It's not the greatest thing to come along since sliced bread.

I also don't give a damn if you think I'm rude or not.  Opinions are like a**holes...everyone has one.