50 Beowulf wildcats?

I found myself thinking about what might be possible through trimming and necking .50 Beowulf brass to a smaller caliber. Perhaps something invalidates this? Else it is interesting to consider a larger cased magazine length cartridge.

You'd end up with something similar to the .458 SOCOM or the .475 Tremor.

Why not just straight wall the grendel case out to .44 or .40 cal? That way you use the same case heads and don't have to bore out your standard ejection port for the fatter cases. Another benifit would be that you get the same ammo capacity weather you use 6.5 G or .40/.44x39

Daniel, Coolhand, I am a neophyte and it is going to show.

I was thinking of a smaller caliber, .308 for a starting point. Is it be theoretically possible to get magnum performance from this combination, or will the AR-15 bolt thrust limitation interfere?

I'd like to see what a 44 Grendel could do. :)

Why not just straight wall the grendel case out to .44 or .40 cal? That way you use the same case heads and don't have to bore out your standard ejection port for the fatter cases. Another benifit would be that you get the same ammo capacity weather you use 6.5 G or .40/.44x39

.429" would be too wide. There is limited selection of heavy bullets in .400". Marty ter Weeme of Teppo Jutsu has played with loading the 10mm iAi Magnum case with 190gr Barnes X spitzers pulled from muzzleloading sabots. This is then loaded in 6.8mm SPC magazines.

My thought for a straight wall Grendel case would be to neck it up for .410-.411" size projectiles. You could conceivably load anything from 170gr .41 Magnum projectiles up to 400gr .411" rifle projectiles.

I was thinking of a smaller caliber, .308 for a starting point. Is it be theoretically possible to get magnum performance from this combination, or will the AR-15 bolt thrust limitation interfere?

I think at best you'd get .308 to .30-'06 performance. I also suspect that bolt trust would quickly become an issue.

Using a .308 as a base line, you would need to go up to an AR-10 as a baseline rifle. The AR-15 couldn't handle the opening of the bolt face (which is why the Beo has a .445 case head diameter rather than a .458 case head diameter like the 7.62 nato), not to mention the OAL of the 7.62x51 would dictate an AR10 stroke length, and magazine well.

Just as a point of note, the 7.62 NATO and the .45 ACP share the same external case head dimensions.

We are talking about necking the Beowulf case down. We do not intend to shoehorn the 7.62mm NATO itself into the AR-15; we merely wish to duplicate its performance within that platform. I'm basing my projections upon the Beowulf's case diameter vis-a-vis the Winchester Super Short Magnums (WSSM). There are proprietary AR15 uppers available for the various WSSM, but their larger casehead requires a non-standard bolt and barrel extension among other changes. Using the Beowulf case instead of the WSSM skirts the bolt issue, but I would imagine that you couldn't push a necked-down Beowulf case to as high of pressures as the WSSM.

FWIW: Olympic has been playing with a '.300 WSSM' wildcat.

Daniel, your mention of a .30 WSSM caused me to look at the Olympic Arms line again, and now with this context to realize that they are getting around the bolt thrust issues. The WSSM is a 62,000 PSI cartridge I believe, with a large diameter case and correspondingly large bolt thrust. Why must the smaller diameter 6.5mm Grendel be limited to (IIRC) 49,000 PSI?

Olympic says: "...the K8-MAG is outfitted with proprietary high pressure bolts..."

If this makes the difference, why cannot the Grendel be equipped with the same?

In answer to a couple of questions,

Re, the 50 Beowulf uses handgun brass, not rifle brass, it is not designed to handle the pressures that rifle brass is designed to.

I have given thought to doing the same thing years ago, including basicially making a short 6.5-284... However, it is a pain to push a should back .5".

As far as the WSSM bolts, if you take the area in inches of the WSSM case head and multiply it times 62,000 PSI, you will get an idea of the bolt thrust the WSSM cartridge places on the bolt and locking system. Doing the math for the WSSM, Grendel and .223, you will see the exponential effects of case head diameter on bolt thrust.

The Grendel bolts are already made with high strength materials. The factory loads are held to a max of 50,000 PSI to ensure very long component life and high levels of safety.

The interesting thing about the WSSM is the accurate barrel life has been reported to be as low as 400-600 rounds... Winchester themselves has had trouble with barrel life. It makes sence since the 243 Winchester is not kind on barrels and making the bullet go even faster is not going to make the barrel last longer. Guess if the barrel wears out, it is hard to see how long the bolt lasts.

In contrast, there are already Grendel's out there with 3,000 to 5,000 rounds down their original barrels.

What a fascinating idea!, necking down the Beowulf, imagine a 7mm Rem Ultra mag reamer put in short, set headspace wherever you want, and cut down a set of dies accordingly. Now you have a 7mm in a AR with 40gns? case capacity. I LIKE IT!!!
Pic below of my latest AR in 6.5x39, because we can't get Grendel here in New Zealand :(

Sounds like they need to invest the time and money on barrel life extension technology, such as progressive gain twist rifling, polygonal rifling, and sabots, not to mention new, more wear resistant materials. Leaps in this field would benifit all firearms. Just imagine a SAW whos barrel life matches or exceeds the reciever life.

Thank you Arne! I knew you'd have a good answer. :)

I guess I should post again... Beowulf Brass is handgun brass manufactured under contract by STARLINE... It is not a good starting point for a rifle project.

You would be better off taking a .284 Winchester case and pushing the shoulder back.

Other subject - Overbore cartridges have always played havoc on barrels. The .223 WSSM is no different then the other famous cartridges as a 220 Swift. A bullet moving extremely fast is going to cause friction and friction between metals is never good for long life. Coatings such as Moly attempt to reduce this fricition, but in the end,, all mechanical things will wear out if there is friction involved.

Regarding the AR15, there are limits of the locking system and the overall design... Given that the AR15 is approaching the end of its military service life, it is not a major priority to upgrade it with new engineering and advanced materials to let it shoot extremely hot cartridges. When you consider that cartridges like the WSSM series develop over double the bolt thrust of the 223 Rem and the gun was designed for the .223 Rem, you can see the hesitation in sticking a large case head diameter / high pressure round in it.

Personally, you would not catch me shooting a WSSM AR15 loaded to 62,000. I have yet to see the engineering or the extensive failure testing of the bolt design to tell me it can truely handle double the bolt thrust for 3,000-5,000 rounds.

If you have ever had a case rupture in an AR15, you will understand my caution.... nothing like having the magazine follower, spring and floor plate blow out of the gun (leaving the mag body) as the gases blow by a blown out extractor. I have also seen an AR15 in .223 Remington experience a total failure with the reciever in pieces on the ground... Thank God, the shooter was not injured.

Arne:
I tried to get a 6.5/284 built in a gas gun but no one would touch it unless you wanted to do limited hand or mag feeding for competiton. I settled on a 260 because it could come very close to a 6.5/284 with longer barrel life. When I looked into the WSSM line I saw several loads that even exceeded the 62,000 psi and was also curious about the component testing to support them. Assuming they have a legal staff I can't believe Oly could market a 243 and 25WSSM gas gun with out extensive testing. I have a 243 AI with 1400+ moderately loaded rounds through it that still shoots 1/2 MOA with a fairly inexpensive Douglas barrel on it. I suspect the WSSM series of cartridges has barrel life relative to the way it is loaded. Even at 500 rounds you will put a lot of pelts on the stretcher using it as a walking varminter before the barrel burns out as opposed to a competition shooter that could do it in a day. The 243 and 25WSSM Oly's I've seen are claiming easy 1/2 MOA but you rarely see anyone posting groups that aren't breathtaking. I've also seen reports of excessive fouling especially in the 243 WSSM. Oly told me they will be introducing a 7mm and 30 cal WSSM before they do a 6.5 WSSM which I am interested in. They claim not enough intrest in 6.5. The other limiter for a WSSM gas gun as a varminter is magazine capacity which is 6 rounds. Leitner-Wise is coming out with a quad stack magazine that may solve that problem. Assuming the body bag count stays low I think a moderately loaded 6.5 WSSM could give my Grendel a run for the money.

rdreeszen, I was mistaken, the WSSM has a MAP specification of 65,000 PSI (http://www.findarticles.com/p/articles/mi_qa3623/is_200308/ai_n9264603#continue). I too hope Olympic Arms has made sure the system is safe, but what Arne has written gives me enough pause that I will leave such high pressures to the AR-10, BAR, and bolt gun shooters for the time.

Arne, you say that the AR-15 platform is old, and I infer a negative sense to that. Perhaps I read that wrong, but it surprised me. Is there a superior rifle and/or cartridge available now or on the horizon that we should be looking at instead?

Finally, are the billet uppers designed & tested to handle a higher pressure?

Disciple

In the military world,,, the AR15 platform is over 40 years old. Not a negative statement, just a reality that we must recognize.

We have seen very recent attempts at a replacement with the OICW, XM8 and now the SCAR. OICW was a cool concept, but technology cant deliver it at a practical cost. XM8 is nothing more then a phased implementation of the OICW process, but that appears to be in trouble. SCAR has been awarded to FN and is progressing to the best of my knowledge.

On any new cartridge in a platform, you have two options,,, build based on validated limits or perform extensive failure testing and that is expensive..You cant failure test one rifle or two since it is not a valid sample. You must also be able to run them to failure, not just a handful of rounds and see what happens. Imagine just the ammo cost of taking 50-100 rifles and running them to failure to determine the threshold? Shoot 50 rifles, 5000 times each at a buck a round (WSSM ammo aint cheap) and you have $250,000 in ammo cost, if they run to 10,000 rounds,, that is $500,000 in ammo plus the cost of the guns and labor to do the testing.

Will a company build something without all the testing and take their chances? Yes, companies do it all the time in many industries and attorneys make lots of money filing suit when things go bad. Of course, if the company is small, they just go belly up and nothing is left to go after.

The Billet uppers have more material in them and are more rigid then a standard receiver. The limiting factor in the AR15 is not the receiver, it is the barrel extension / locking lug system. Force is being applied to a finite area and yes there some pretty exotic materials that can increase strength, but to validate the benefit of the exotic materials requires expensive testing that is beyond the limits of almost anyone but the military. Of course, even if validated, would you pay $1000, $2000 or more for a single part made of some high tech alloy or ceramic? If you are building a space shuttle, maybe.

I guess I should post again... Beowulf Brass is handgun brass manufactured under contract by STARLINE... It is not a good starting point for a rifle project.

You would be better off taking a .284 Winchester case and pushing the shoulder back.

Other subject - Overbore cartridges have always played havoc on barrels. The .223 WSSM is no different then the other famous cartridges as a 220 Swift. A bullet moving extremely fast is going to cause friction and friction between metals is never good for long life. Coatings such as Moly attempt to reduce this fricition, but in the end,, all mechanical things will wear out if there is friction involved.

Regarding the AR15, there are limits of the locking system and the overall design... Given that the AR15 is approaching the end of its military service life, it is not a major priority to upgrade it with new engineering and advanced materials to let it shoot extremely hot cartridges. When you consider that cartridges like the WSSM series develop over double the bolt thrust of the 223 Rem and the gun was designed for the .223 Rem, you can see the hesitation in sticking a large case head diameter / high pressure round in it.

Personally, you would not catch me shooting a WSSM AR15 loaded to 62,000. I have yet to see the engineering or the extensive failure testing of the bolt design to tell me it can truely handle double the bolt thrust for 3,000-5,000 rounds.

If you have ever had a case rupture in an AR15, you will understand my caution.... nothing like having the magazine follower, spring and floor plate blow out of the gun (leaving the mag body) as the gases blow by a blown out extractor. I have also seen an AR15 in .223 Remington experience a total failure with the reciever in pieces on the ground... Thank God, the shooter was not injured.



The only WSSM that makes much sense to me is the .25.


I'd like to see it at .30 and .375. :D

Arne:
I tried to get a 6.5/284 built in a gas gun but no one would touch it unless you wanted to do limited hand or mag feeding for competiton. I settled on a 260 because it could come very close to a 6.5/284 with longer barrel life. When I looked into the WSSM line I saw several loads that even exceeded the 62,000 psi and was also curious about the component testing to support them. Assuming they have a legal staff I can't believe Oly could market a 243 and 25WSSM gas gun with out extensive testing. I have a 243 AI with 1400+ moderately loaded rounds through it that still shoots 1/2 MOA with a fairly inexpensive Douglas barrel on it. I suspect the WSSM series of cartridges has barrel life relative to the way it is loaded. Even at 500 rounds you will put a lot of pelts on the stretcher using it as a walking varminter before the barrel burns out as opposed to a competition shooter that could do it in a day. The 243 and 25WSSM Oly's I've seen are claiming easy 1/2 MOA but you rarely see anyone posting groups that aren't breathtaking. I've also seen reports of excessive fouling especially in the 243 WSSM. Oly told me they will be introducing a 7mm and 30 cal WSSM before they do a 6.5 WSSM which I am interested in. They claim not enough intrest in 6.5. The other limiter for a WSSM gas gun as a varminter is magazine capacity which is 6 rounds. Leitner-Wise is coming out with a quad stack magazine that may solve that problem. Assuming the body bag count stays low I think a moderately loaded 6.5 WSSM could give my Grendel a run for the money.



Thanks for the tip, I've been wondering when someone would bring out a 4 stacker..
I forgot to mention I'd LOVE to see a 6.5 on the WSSM. My dad likes 7mm a little better, but...

Disciple



The Billet uppers have more material in them and are more rigid then a standard receiver. The limiting factor in the AR15 is not the receiver, it is the barrel extension / locking lug system.


I examined an Oly wssm upper at a gunshow a couple of weeks ago. I belive it uses a larger diameter bolt & barrel ext. The lip on the boltface looked kinda thin to me at a casual inspection. I have talked to a person involved in the devolpment of this upper & they claim to have tested one to destruction.
They loaded a caseful of unspecified fast burning rifle powder & couldn't get it to let go. Finally after a caseful of bullseye the case melted & the carrier failed & blew pieces out the mag opening. The barrel had a slight bulge at a thread relief groove on this prototype that is not present on production barrels but remained intact as did the bolt. He was very adamant that the barrel would fail before the bolt lugs. At least thats my memory of his account. My memory isn't perfect so don't hold me to it.
I have been interested in shortning a WSSM case to about 1.5" overall with at least a .250" neck so as to free up some room in the mag for a longer bullet. This would make for a short fat single feed M16 conversion in 6.5 with more powder capacity than a Grendel with the advantage of using slightly modified GI mags. The factory cases are 1.670 in length. I think this would be to long to load the best long heavy 6.5 bullets in the mag & would limit it to very light bullets. A .223 WSSM might allow 80 grain sierras from the mag.

For comparisons here are the lengths.

5.56 nato- 1.760" or 44.7 mm
.243 WSSM- 1.670" or 42.4 mm
.220 russian - 1.523" or 38.7 mm
Proposed 6.5 on shortened WSSM case- 1.5" or 38 mm.

Could need to be even shorter, I suppose. I haven't gotten beyond mulling it over in my head yet. Need to get some cases & long bullets & play with them I guess. Need to keep neck length in the neighboorhood of .250 to .300 IMO as too short a neck can degrade accuracy. Anyone know of a formula for computing optimun neck length? I know from a lot of shooting with Army MTU years ago that a 30/338 gives better accuracy than a 300 win mag & the only real difference was the MTU cartridge (30/338) has a longer neck.
I also think that the reason a .222 is intrinsicly more accurate than a .223 is the longer neck.

Actually if you want to use double feed in an issue mag, the 5.45 X 39 Russian is interesting because of its .394 base diameter & 1.555 or 39.5 mm length. this should allow 80 grain sierras from the mag & one could improve this case( it has a 20 deg shoulder) & might end up with a usuable modest increase in powder capacity over the 5.56 nato. That of course depends on a brass case, so far all we have is steel too my knolwledge & the neck is on the short side at .220.

I have talked to a person involved in the devolpment of this upper & they claim to have tested one to destruction.

testing one to destruction is not testing the design across a series. IMO, if you are going to test the design, you are going to test enough samples to validate that the parts represent a true range of the production item... If you only test one,,, it could be a weak one or could be a "lucky" one.

Given the barrel life issues of the 223 WSSM and 243 WSSM,, the bolt may last longer then the throat. Either way, 60,000-65,000 PSI on a very large bolt head is alot of bolt thrust.. (seem to remember calculating it to being over double the bolt thrust of a .223 Rem)

Having a case rupture (had that one happen) or a catastrophic let go (saw that too from a barrel obstruction),,, is not something you want to have happen with your face inches from the receiver.

Having a case rupture (had that one happen) or a catastrophic let go (saw that too from a barrel obstruction),,, is not something you want to have happen with your face inches from the receiver.


I have experenced a catastrophic let go. It was an Egyptian Hakim (8mm Mauser using a licensed Swedish lungmen semi-auto design.) I was firing some forgotton unheard of east european soft point Round nose hunting ammo with the bullets seated too long for this rifle ( short throat) . A Hakim bolt shuts with a great deal of force & it chambered & seated the bullet deeper into the case & I pulled the trigger from the prone position. I didn't notice anything wrong & proceeded to fire again & got click. When I pulled the bolt open not only was the chamber empty but I could see daylight down through the receiver as if the mag had been dropped. I then turned the rifle belly up to examine it & the mag had exploded & only a few remanants of it were still locked into the weapon. The stock had swelled & cracked & the trigger guard/floorplate was warped & cracked also. Interestingly the action itself suffered no harm from this. Egyptian issue ammo for this rifle uses very pointed bullets & does not cause this problem. The RN long seated ammo worked fine in my 98K but was way too long for the Hakim. I'm not sure if it was overpresure from jamming the bullet deeper or if the rifle fired out of battery. M9

testing one to destruction is not testing the design across a series. IMO, if you are going to test the design, you are going to test enough samples to validate that the parts represent a true range of the production item... If you only test one,,, it could be a weak one or could be a "lucky" one.

Testing one to destruction doesn't mean they didn't test more. I expect they tested many more. In our conversation we were discussing this one. That does not exclude others. Just because it mounts on an AR lower does not mean it is subject to the ARs limitations. If this was true how would you explain a .50 BMG upper? I expect that produces more bolt thrust than a .223 WSSM & I expect it is solved with pysically larger parts as is a WSSM conversion. Your argument would be more valid if they were using modified AR bolts, but they are not. I do agree that it is a new design as is the Grendel & neither has stood the test of time yet. M9