I've been working on a project for quite a while, and it is starting to come to fruition.  It's called the .277 Wolverine, and basically it's a 5.56 case with a 6.8 bullet in it.  Designed to use standard 5.56 mags without modification, 5.56 bolts, etc.  All you need is a .277 Wolverine barrel and a set of dies and you're out shooting.

Below is some basic info, and here's a link to the .277 Wolverine section on my website:

< No linking to your commercial website unless you're an ARFcom vendor - F >

Update:

02-01-14 - Test barrel received, talked to Hornady, test dies should be here in 2 weeks.

01-21-14 - Received Tracking number form Pac-Nor. Barrel en route! Carbide Rouger and Finish reamer in. Headspace gauges in. HS finish reamer in. Barrel stub coming from Pac-Nor as well. Brad at Sheridan Engineering has agreed to manufacture .277 Wolverine Slot Gauges. Little Crow has agreed to manufacture .277 Wolverine WFT's. ARP has agreed to manufacture production barrels. Hornady has agreed to manufacture die sets.

01-21-14, Test Die Set delivery pushed back to Mid-February...

Test Dies:

Hornady New Dimension Two-Die Set

Test Barrel:

Pac-Nor 16" Stainless, 5R 1:11.25 (ARP's Button), Mid-Length Gas, .086 Gas Port, threaded 5/8-24, Hunting Crown, M4 Extension

Upper Build:

Pac-Nor barrel, Syrac Adjustable gas block, Mil-Spec Middy Gas tube, Aero upper, Colt F/A Carrier, ARP 5.56 Superbolt

Optics:

Trijicon Accu-Point 3-9, Amber Dot, Mil-Dot Reticle on a LaRue LT-104

Relative Lower Components:

Standard Carbine Buffer and Spring

Bullets to be used for initial testing:

Speer 90 Grain TNT
Barnes 95 Grain TTSX
Hornady 100 Grain SP
Nosler 100 Grain AccuBond
Sierra 110 Grain Pro-Hunter
Hornady 120 Grain SST

Proposed Powders to be tested with various weight bullets:

1680
Lil' Gun
Win 296/H110
H4227
Re7
LT-32
AA2200
H335
Norma 200
Vihtavouri N-120
IMR 4198
H 4198

Proposed Primers to be used:

CCI 41
(Other?)

Production Barrels to be Ordered:

Batch 1 - ARP 16" Scout Profile, threaded, melonite, mid-length gas
Batch 2 - ARP 12.5" Pistol Barrel, threaded, melonite, mid-length gas
Batch 3 - ARP 18" SPR, Target Crown, melonite, rifle gas
Batch 4 - 10" 1:7 Sup/Sub Barrels... Manufacturer TBD


There are a few things I need to say that will hopefully stand out immediately to anyone reading this to avoid some questions/comments:

1) This cartridge is in NO WAY meant to compete with the 6.8SPC's velocities. It simply can't.
2) I am not an engineer, machinist or physicist. Let's make that clear. I am receiving great guidance, however, and am pretty resourceful.
3) I had an idea, and am seeing it through. I'm not going to be disappointed if some people don't like it.
4) The name of the cartridge is the .277 Wolverine, and it's metric designation would be the 6.8x39, but has nothing to do with the 7.62x39, case or otherwise.
5) The Wolverine part has nothing to do with fantasy characters... it is a blend of the animal's reputation (small but ferocious), and, I happen to be a huge fan of the movie Red Dawn (The Original Version!) so there's my little personal touch.
6) I am funding this entire project on my own, and farming out most of the work so that is why it is taking longer than I want, and costing me more than I want to bring it to fruition.
7) This cartridge is not meant to be a long range DMR, Sniper, or any other long range application. Sure, you could launch one out there, but that's not the intent. The intent was to produce a CQB/Mid-Range cartridge using a 5.56 case/mags/bolt but with a 6.8 bullet. That simple.


Basics:


5.56 parent case, 6.8 bullets.
Standard AR15 5.56 bolt
Uses standard AR15 5.56 Mags (Testing about 8 different brands shortly including Pmags)
.277 Wolverine Barrel and Dies or other way to produce ammunition all that is needed


Case:


Parent cases used for first die set was Lake City 5.56 NATO
Trim length 1.535
Shoulder bump .20
Neck Length .23


Bullets:


First test bullets will be 90 TNT's and 110SPH's to show some basic versatility
Second run will be 95TTSX 82Raptor, and a few others once powder combo's dialed in
The "Smaller" .270 bullets (6.8 bullets) between 80 grains and 110 grains are ideal
120 grain SST, 130SP's, etc. are a little heavy for this but I'll try them, too.
200gr. Woodleigh bullets look like good sub/sup candidates


Ballistics:


TESTING FOR ACTUAL RESULTS IN FEBRUARY 2014
Expecting results of a 90 TNT at around 2600fps and a 110SPH at around 2400fps out of a 16" bbl.
Will test a myriad of powder/bullet/load combinations and will post results of any pressure signs, accuracy, velocities and function.



Concept Cartridge Case Drawing:

From left to right: 5.56, .277 Wolverine, 300BLK, 6.8SPC

I value everyone's feedback.  I'll answer as many technical questions as I can, but like I said above, I'm no engineer or physicist so if I don't know the answer I'll get it for you.

Thanks,

-Mark

Reserved....

Reserved...

Interested in seeing how this develops... keep us posted!

Good luck!

I've wondered why noone has done this yet.
My thoughts were more with a 6.5mm bullet though. They seem to have the best bc.
Good luck op, keep us posted.

has been done with 6.5  6.5 pcc


looks like another caliber i am going to have to put in the stable, i am a sucker for a 223 based wildcat.

Cool.  Tagged for reading interest.

Mark best of luck with your new cartridge, sorry we did have time to get together last week to discus the development of the .277 Wolverine and the 6.8mm PCC rounds...
but I am sure it will work out great for you, as both the 6.5mm/.264 & 6.8mm/.277 variants seem to be the sweet spot for the AR-15 platform...although the 6X45 and the
25-223 rounds are also very appealing....

Again best of luck, I know it will do well for you and keep in touch.

Thanks Vic and yes sorry our paths didn't cross while you were in town.  We'll have to make it up somehow.  We will definitely keep in touch, and I'll keep an eye on your progress as well.  I appreciate your input.

I am most interested in how the high sectional density rounds work in that case.

I like the name

I bet it would perform great in 8 - 10.5 barrels.

THS still lives... at least on this forum

I am hoping a 90 grain gold dot type projectile does good out of this cat.

< And another commercial non-vendor link removed - F >

Everything was going great until I read what is highlighted in red.  The remake f'in killed me!

Forgot what was written in red after I read what is highlighted in blue.  Kudos.

Big fan of the 6.8 SPC, however I would have no problems dropping it in favor of a cartridge with more commonality of the 5.56 components.

I was thinking to myself the other day how the 6.8 projectile on a 5.56 case could definitely be a good thing.

Thanks all. I'll get Chrony results posted mid-March.

I am still considering this for a future build.

I will be interested to see what the burn efficiency is and if barrel length will impact velocity similar to 300BO. I look forward to it being ceveloped from here on out.

Expect an IM on some colaboration work.

There have been quite a few people who have said that they were going to do this (the PCC people, the 6.8 Kramer something, etc) but none have gotten off the ground. I think there is a niche here (witness the 300 blackout and the 7.62x40 as well as the 25ar 6x45 etc).

These 6.8 (and 6.5) .223 variants are definitely a good thing.

From what I have seen, they are giving approx. ~80% (or more) of the performance of the 6.8 SPC (and 6.5G), but out of a .223 case.  That means using standard bolts, standard mags, and of course, the plethora of inexpensive .223 brass that is available in the US.

They are also carrying ~1,000ft-lbs. or so of energy to 300y w/ very good external ballistics.  That's pretty awesome from a .223 case.

With the help mark is getting with this, it has possibly the best potential of any small company start-up caliber this side of 300BO. I think it will perform quite well and I intend to try them myself.

Good on ya', OP.  Nothing moves as fast as you would like it to, but if it was easy, someone would've already done it.  Due to the reduced diameter, specialized cans might be quieter than the .300"Whisper.

The 6.5mm PCC version has been in production for about two years now, the 6.8mm PCC version is awaiting final print approval and reamer delivery
from reamer manufacture...Industry/Vendor delays are the killer, as well as considerable amounts of pre-payment funding needed to get things rolling...
as I'm sure Mark will attest to...

Oh I attest... This thing has been going on since August... Paying for it all myself. I have barrel maker, die maker, WFT's, Slot Gauges, Reamer and Headspace gauge makers, even brass converters all lined up and ready for me to drop payment and say "go".  Took a while, but so far it's been worth the experience.

Building the test upper this week/weekend, having an independant party conduct the load/ballistics testing so that there are no misgivings or bias behind posted data, and then providing a live fire demo to a group on March 30. April 1, I will be placing orders with the aforementioned providers for barrels, die sets, WFT's, Slot Gauges and whatever anyone wants. Figure 5 months or so from there, everyone gets their stuff. Then, next rotation begins.

Oh and thanks for the support fellas, I appreciate it. I really believe in this cartridge and I think folks will see the value in it once I'm able to post the range results and talk more about bullet choices that are available, from 80 grains to 110 grains.

Which 223 variants give more than 1000 ft lbs at 300 yards?

IIRC, the 6.5 PCC & 6.8 PCC are both in the ~1000ft-lb range @ 300y.

I believe the .277 Wolverine will be close as well, maybe around 900-950ft-lbs. @ 300y.

As for your question, I know of no 223 variant that gives more than 1000ft-lbs @ 300y.

If all you're chasing is energy at 300 in a 223 variant it's gonna be tough to beat the 7.62x40 with a 125 or 135 boat tail....numbers are right at a 1,000 or a tic over depending on barrel length....a flat base 125 will post numbers in the 900 ft/lb range at 300 yds...

7.62x40 + 125BT + 2,600fps = ~ 1,025 ft/lbs @ 300 yds
7.62x40 + 125FB + 2,600fps = ~ 900 ft/lbs @ 300 yds

for a 277 variant to hit 900 ft/lbs with a comparable flat base bullet at 300 yards it would need to have a muzzle velocity of over 3,100 fps.....ain't gonna happen...the conventional 277 boat tails encroach on capacity when they get to a 'useable' BC....

Probably see something more like this:

277 variant + 90FB + 2,900fps = 760 ft/lbs @ 300 yds

Thanks for the run down.  



I'm curious, what pressure are those 125gr 7.62x40 rounds you listed loaded to?

A lot less than the 90gr 277 at 2,900fps  

According to the Hornady Ballistic Calculator for the 6.5mm PCC round:

100 gr. Hornady A-Max @ 2,800 fps: 1,742 Ft/Lbs of Muzzle Energy:

Drop in Inches @ 300 Yards = 13.8
Energy @ 300 Yards = 1,031 Ft./Lbs.
Velocity @ 300 Yards = 2,255 FPS
+ 4.4 MOA, + 1.3 MILS

What length brl would this be & are you talking about your 6.5?

Some of our 20" barrels have come close to that number, and our 22" will exceed that by a bit...Check
some of the very recent field results by ARF.com member Hilljack on the 6.5 PCC thread...

I think the best pills for the .277 Wolverine will be in the 85 gr. to 100 gr. range considering the design and
limitations of the AR-15 platform & magazines etc.

This cartridge was designed to use 6.8 projectiles and standard AR15 parts (except the barrel) specifically, so there are some trade-off's.  1,000 ft/lbs of energy at 300 yards is not going to happen unless a revolutionary propellant comes about.

It will, however, deliver 750+ ft/lbs out to 300 yards which is more than enough for two-legged and some four-legged critters out there... which again is by design.  As stated in post 1 it was not designed to be a DMR, Elk hunting cartridge, etc.  The compromises are this - the case was shortened ever so much more than what might be desired to allow it to function using standard 5.56 AR15 magazines, without modification, and reliably feed an extract thus the same case taper and shoulder angle.  That simple.  This cartridge will shine in the 85-100 grain bullet arena the most... which if you compare to the 77SMK allows for "more better" hunting style projectiles delivering more energy on target with expansion capabilities.  I can't really see anything past 300 yards, let alone hit it LOL.  I wanted this for 300 and under... in a lightweight platform, and mostly for deer, hogs, varmints, etc.  This will not kill an elephant at 450 meters... unless you want to get into the shot placement debate, to which I LOL again.  I wanted a little bit bigger and heavier bullet than 5.56, but with better trajectory than the 300BLK.  I don't bash either of those cartridges, though as I own 5.56 rifles with pride and I think the 300BLK has its uses, too.  I also like the PCC designs and the WT's... I just went with something a little different.

At the end of the day, I wanted it to be what it is, because that's what I wanted, and so that's what it is.  I won't post inflated numbers or try to tell everyone they should buy one, but, once I get the live ballistics results posted you can decide if you're interested.  I'm not going to say mine's better than yours or whatever... I'm too old for that crap.  I just wanted to make one and did it even though I have limited internal and external ballistics experience.  I have learned a ton since I started.  I've had a lot of help with this, and for that I'm grateful.

Appreciate everyone's insight and the technical discussions as it is very helpful as well.  I just hope no one ruins this thread with the usual mine vs. yours vs. theirs chit.  There's one of those happening on every forum and I don't want to be a part of it.



Edit:  Was typing while you were Vic, thanks...  and to clarify, I like the comparisons, I just don't like the childish bickering that tends to happen so glad that so far that hasn't happened.  And thanks for chiming in, Kurt, as well.

I think it's great that so many people experiment to solve shortcomings..... I like what you are doing here.  

There are also people working on a chambering for the 223 case with 90 gr VLD Bergers fed  from 6.8 mag and achieve over 2900 fps out of 24" barrel and around 2850 from20".  With the BC of that bullet it would give 1125 or 1080  lb/ft energy respectively.  It would only require a new barrel and 6.8 mags for longer feeding.  

Can't wait till you get your barrel and start testing your loads Mark...Actually time wise you did pretty good so far getting everything together...I know it will do well, I will
email you some Industry contacts that may be of help to you for your development work tomorrow. I also have a ballistic software program that may be of help to you
as well...

Thanks Vic I'll take all the help I can get. Barrel is here, upper almost done, testing starts March 2.

Ready to go... just gotta' make some ammo...

Looking good...Program CD is on the way.

Going to be watching this with some amount of interest.  Love the name!  Always been a wolverine fan, the only animal that can take on a grizzly and win for a meal at 1/10th the weight, awesome!

Just a side note though;  been having some difficulties with 5.56mm magazines in the 6.5 PCC.  The alignment ridges that are used to guide the 5.56mm heads are not that great and even compress the cartridges of the 6.5 PCC in, as I am sure this will happen with the 6.8mm rounds.  One fix is to use a 6.8mm magazine and a 5.56mm follower.  Was able to fill the magazine to capacity and have zero FTFs out of my AR.  If you also want the maximum length out of your cartridge, I would also start looking at the PRi magazines for this purpose.  They will accommodate up to 2.300" COAL set rounds.  Good luck and stay safe.

Thanks... the cartridge was designed (x39), so that they function in standard 5.56 AR mags without modification... the front rib you speak of inside the mag, rides on the approx. .257 portion of the bullet ogive rather than on the neck.  That's why it's able to work without binding.

Another guy suggested trying 6.8 mags with a 5.56 follower and I will do that, thanks!

The 85 tsx is a pretty sweet projectile. If you can get the velocity up there, I'm interested.

Posted Via AR15.Com Mobile

My guys and others with 6.5mm/6.8mm/7.62mm wildcats based on the .223 Rem case have been going that route, that is
using .6.8mm SPC & .300 Blackout  dedicated magazine bodies with .223/5.56mm followers and has seemed to have
work well (also using Lancer made Wilson 7.62X40WT mags has been running about 100% reliable with a 2.269" COL).

The PRI 6.8mm SPC mag bodies with .223/5.56mm followers seem to do the trick as well and give long 2.300" COL...
as mentioned earlier...

The Mercedes Benz of the .223/5.56mm mags is still the HK-416 Marine Steel Mags with no mods, 100% reliable and
long 2.300" COL capable...

ASC and Pmags also work well with little to no mods, but you will have load to a lower count for reliable feeding...

Since the .277 Wolverine uses a shorter case length it is less likely to have magazine Issues...

Thanks and good luck.

Nice.  Good to see someone with the dedication to work through a project like this. I know its not easy....

Keep us updated.

Thanks Vic!

And thanks everyone else for the support... it is not easy... but we're right around the corner.  Gentleman doing the testing got impatient and just made a die and a demo dummy round, looks good!  Sending him all the equipment on Tuesday.

Tag for interest.
I have been waiting on this cartridge. I don't want a short barreled, suppressed .300 BO. I just want to be able to hunt at 100-150 yard ranges with my AR and I don't like that the 6.8 SPC isn't compatible with bolts/mags.

Tagged for testing outcome. This looks interesting, and I have been wanting to get into some kind of a .277 round. This may very well fit the bill.

Cool.  Can't wait to see the test results.

Upper and supplies ship out tomorrow to tester...  should have some results posted in the next couple weeks.  So far case capacity is looking really good after loading 90 TNT's to 2.190 and 95TTSX to 2.255.

OP, interesting!  Several years ago while shooting IHMSA, unlimited division,  I built a XP 100 for this.  I took a 223 case, necked it up to .270 caliber and had a .270 barrel installed.  At that time I was using 130 & 150 Sierra bullets.  I was looking for a gun that was easy to shoot, but has enough energy to knock over the ram targets at 200 meters.  It did real well.  I have no idea with the FPS's were.  It just know that it shot well and I took matches with that gun.

Ran some numbers on the ballistic computer program for the .277 Wolverine, Input as follows: [Please note: these are projected computer loads].


Powder: Alliant 2400--Projectile: Nosler Spire E-Tip 85grs. .277 Cal.-- 20" Bbl.--28.0 grs (H2O) Case Capacity--Case Trim Length: 1.585"--COL: 2.260"


Maximum Charge: 20.2 grs.--Velocity: 2,752 fps.--Energy: 1,430 Ft./Lbs.--Peak Chamber Pressure: 50,000 CUP [Maximum].
Max.Charge w/ Barnes TSX-FB 85gr. Charge:  21.2 grs.--Velocity : 2,773 fps--Energy:  1,452 Ft./Lbs.--Peak Chamber Pressure: 50,000 CUP [Maximum].

Chances are in field testing results may be more robust...As always use common sense and proper reloading techniques and caution when
developing any rifle/pistol loads...These loads are computer generated and are not meant as a loading guide, use at you own risk.

Thanks Vic but the case trim length is 1.535-1.540 max, and we seated a 90 TNT last night to 2.190 OAL and the base of the bullet was at the base of the neck, which I'm told left approx 21 grains H2O case capacity.