Fastest .224 cartridge in a semi-auto?

[Potss]

...and not the earschplittenloudenboomer! To be more specific, which cartridge will launch 62gr-77gr (so not light 40-50gr but no need for the 80-90gr either) bullets the fastest from something around the size of an AR10 (so I'll like .22-06 slide) in a semi-automatic fashion.

I'm thinking about a build for a semi-auto "flatter than flat" shooting rifle. Also just interested to see what is out there.

So far I have in the large frame AR10, the .22-243, 22Creedmoor, and .22-06 from a Noreen.

And from the AR15 (or maybe ar10?) the .223WSSM, .223BRX, and then any of the 6.5G necked to .224 cartridges.

Thoughts on which would be able to push those 62gr bullets the fastest? Does that change if the barrel is limited to 16in-18in (with a 7in suppressor)? I will be in some brush and trees, don't want the thing to be 24in+7in suppressor.

And no I'm not over concerned with barrel life before that comes up.

 

[Forgetful Coyote]

.22-243 AI running PALMA brass so you can hot rod up the pressures..? That'd be direction I'd go..

 

[nbkky71]

.223 WSSM would definitely be a contender, but I've never had much experience running those stubby WSSM cartridges in an AR upper.

How about .22 Nosler?

 

[Jibnast]

The 220 Thunderbolt by keystone armory is another one to look into.

 

[brent31]

Check out .224 Valkyrie

 

[Potss]

Are folks suggesting necked down 6.8SPC (.22Nos, .224Valk, .220Thunder) because of the barrel length? I just don't see how with the case capacity it has it could ever hope to compete with the .223 WSSM from the small frame. The .223 WSSM has the same case capacity as the .22-243win, and a shorter powder column than the .22 Creedmoor so it shouldn't suffer as much from shorter barrels I'd think. But it is very hard to find reliable data on these rounds, especially on barrels around 18in.

 

[hlee]

All of my reloading manuals list the 223 wssm as the fastest 223 caliber cartridge. But, I would be concerned with the feeding of that stubby cartridge in a semi auto.

 

[Potss]

I'm not really worried about feeding WSSM in an AR15, DTECH has had that figured out for a long time: http://www.dtechuppers.com/ar-15-wss...receivers.html I wouldn't do it myself though you are right, there are a lot of small modifications that need to be made to get it to run properly.

As far as I can tell (getting different numbers from different places) this is the case capacity of the frontrunners:

22-250 Rem---43.49 gr
22-250 AI---46.9 gr
223 WSM----53.7 gr
22 Creedmoor----53.5 gr
22-243----53gr
22-243 AI----54.8gr

So from a raw powder staindpoint the .22-243AI seems to win slightly for what can be chambered in an AR10 or AR15. BUT after reading about case efficiency, it seems like shorter fatter cases get more velocity per grain of powder generally, and this is even more true when using shorter barrels. For example in this article the author cuts a 6mm Creedmoor from 31in to 17in: https://rifleshooter.com/2017/01/6-c...-to-17-inches/ Of note he states that:

"When I conducted a similar test on the 243 Winchester with factory ammunition (link), a 100 grain bullet had a velocity of 2488 in a 16″ barrel. The 6 Creed loads above are all at least 347 feet/second faster with a 17″ barrel (this was with the same methods and chronograph in nearly identical weather conditions). That is impressive (ironically, those tests were conducted a year ago). This disparity was unanticipated since the 243 has a much larger case."

He goes on to say he could have closed the gap more with handloads, but even a 150fps difference is pretty huge considering you are burning less powder and generating less barrel wear and actually getting BETTER performance. I'm also assuming that observations carry over to the more overbore .224 calibers as that is a 6mm comparison. The other question is, since the .223WSSM is about .3in shorter than even the .22CM, would the .223WSSM be even more efficient and even less susceptible to velocity loss in a shorter barrel.

And really the question becomes .22 Creedmoor from an AR10 (if the above is correct if not then .22-243AI), or .223WSSM from an AR15. A lot of pros and cons to both. I'm still curious which would actually be faster, so if anyone has any data on any of those three cartridges from barrels in the 16-20in range I'd be very interested to see it. I've already seen this thread which was a goldmine: https://www.snipershide.com/shooting/forum/...4-22-creedmoor

 

[supratt96]

I have a Dtech upper in 25 wssm that pushes 90 grain bullets at 3700 fps. That's using RL17 and a 22" barrel. The wssm case with the right powder is awfully hard to beat when it comes to velocity. Pretty sure 4000 fps or close to it would be achievable with a 224 wssm and 69 grain bullet.

 

[Greg Langelius *]

Since bore life is not a factor, I won't go there.

More important to me would be the effect of barrel heating upon accuracy. I like the .22-250 for its flat trajectory and excellent accuracy, but never overcame the way it would open up after too few rounds, and then take a long time to cool back down again to the point where accuracy was optimal. I eventually had to abandon my project intending to use it for competitive shooting because there just wasn't enough time allotted to the COF to allow the cartridge's inherently great accuracy to shine in the application. Logically, consideration of an even larger case capacity became impractical.

Then, there's the bullet. I, too like the 62-65gr projectile weight range. I have fired a lot of M-855 surplus. I had problems getting good groups. Disassembling a significant sample, the charge weights were simply the most consistent I had ever seen from factory ammunition, so that wasn't the problem. I concluded that the process of marrying a penetrator with a core and a jacket was not conducive to good ballistic consistency.

But other 62gr projectiles exist and an interesting one is coming out soon. Hornady is reviving (video) the Frontier brand name and basic concept, combining military arsenal manufacturing with Hornady projectiles. One of the offerings will be a 5.56 loading using a 62gr HPBT Match projectile. Assuming the arsenal charge weight consistency remains constant, such a load could be interesting, and hopefully, the new projectile would also become available as a reloading component.

I fully support your project..While it might not occupy a high position on my own list of personal priorities, it is still a fascinating concept. I want to see where it leads; and I sincerely hope my suggestions help you find your way.

 

[Potss]

Thanks supratt96, that is exactly the kind of info I'm looking for. That is what is attracting me to the WSSM and similar cartridges for sure, that speed+BC is so hard to beat. A 69gr TMK or 70gr RDF at 3900fps would be incredible, as would 62gr TBBCs going as fast or faster. Can I ask you how you like your setup, what you use it for, is there anything you'd change, etc?

Greg Langelius, thanks for the advice! I'm curious what barrel and contour were giving you that level of heat shift, and at what kind of ROF? I'm asking because Bartlein and other high end barrel makers have said that with proper stress relief, heat shift shouldn't be an issue, especially in thicker contours. I'd heard support for this as well from end users but I'm not sure if being this overbore changes that equation in any way? If it does end up being problem, I'm going to see if I can convince Falkor to sell me a DRACOs barrel in whichever caliber I end up with and see if that fixes it, which I assume it would. Not to mention it would be pretty easy to test their barrel life claims quickly as you point out.

As for 60-77gr projectiles, I'm not too concerned with getting my hands on the ones I need, but thanks for the links. A bit of a side note here, what twist would be needed to handle that range of bullets, say a 62gr TBBC at the bottom end (or even the 60gr vmax if I can get away with it) up to as heavy as I can go, 77gr-90 whatever is possible. I'm assuming at such high velocities a 1:8 might explode those lighter bullets?

 

[CMH]

I have a Dtech upper in 25 wssm that pushes 90 grain bullets at 3700 fps. That's using RL17 and a 22" barrel. The wssm case with the right powder is awfully hard to beat when it comes to velocity. Pretty sure 4000 fps or close to it would be achievable with a 224 wssm and 69 grain bullet.

I had a 243 WSSM DTECH upper that would drive 65 grain VMAX's just shy of 4,000 fps with RL-17. Not the high BC you would get with heavier bullets in .224, but it was the most devastating thing I have ever seen on varmints out to about 400 yards. Seriously - pink mist clouds and chunks of prairie dog everywhere. I would assume you could do something similar with 223 WSSM. I sold it to get into a 6XC bolt gun to run higher BC bullets, kinda wish I had kept it. Similar to what Greg was saying - it was a fairly high heat application. And you really need to be careful you don't pepper anyone with that brass, because it is HOT and it has a lot of mass so cooling is slow. I didn't have trouble with up to about 10 shots strings, but above that you really had to manage the heat - especially on a hot day.

 

[supratt96]

Thanks supratt96, that is exactly the kind of info I'm looking for. That is what is attracting me to the WSSM and similar cartridges for sure, that speed+BC is so hard to beat. A 69gr TMK or 70gr RDF at 3900fps would be incredible, as would 62gr TBBCs going as fast or faster. Can I ask you how you like your setup, what you use it for, is there anything you'd change, etc?

Greg Langelius, thanks for the advice! I'm curious what barrel and contour were giving you that level of heat shift, and at what kind of ROF? I'm asking because Bartlein and other high end barrel makers have said that with proper stress relief, heat shift shouldn't be an issue, especially in thicker contours. I'd heard support fosr this as well from end users but I'm not sure if being this overbore changes that equation in any way? If it does end up being problem, I'm going to see if I can convince Falkor to sell me a DRACOs barrel in whichever caliber I end up with and see if that fixes it, which I assume it would. Not to mention it would be pretty easy to test their barrel life claims quickly as you point out.

As for 60-77gr projectiles, I'm not too concerned with getting my hands on the ones I need, but thanks for the links. A bit of a side note here, what twist would be needed to handle that range of bullets, say a 62gr TBBC at the bottom end (or even the 60gr vmax if I can get away with it) up to as heavy as I can go, 77gr-90 whatever is possible. I'm assuming at such high velocities a 1:8 might explode those lighter bullets?

I had the 25 wssm upper made specifically for Texas hog hunting at which it excels like no other rifle I have used for that purpose. To say it hits hard would be a huge understatement. It knocks hogs flat where they stand. Besides it's incredible stopping power, the benefits are surprisingly light recoil, quick follow up shots, and good accuracy (typically 1 moa or better). That being said, there are a few downsides. The mags only hold seven rounds. There have been a couple of times when I could have used a larger mag capacity. My upper has a built in compensator (not technically a muzzle brake) that makes it pretty loud. With a short barrel and muzzle device, you're going to have very substantial muzzle blast. Lastly, wssm brass is not the easiest to work with when it comes to reloading. It's odd dementions may require some loading tools you might not have. Not a big deal, but something to think about. Also, the brass is very thick and tough. It requires a good quality press that provides a lot of leverage.

 

[Greg Langelius *]

The rifle was a Ruger 77VT, with a Varmint weight hammer forged barrel. I had 2 at the time, a .308, and the .22-250, but they were sold in a period of financial stress. The issue, I believe, was not a matter of barrel stress but rather one of load tuning, where the load went out of tune as the barrel heated. I have since changed my load development routine, doing my load testing with a preheated barrel. It seems to help.

I had since entertained a hope that I would be able to acquire a Lothar-Walther Lightweight barrel, which combines a thin core barrel in a thermally fitted aluminum jacket and sheds heat in a remarkable manner, but this product has recently become unavailable on their site. I suspect the high asking price limited sales to the point where it became uneconomical to produce. I think a faster twist (1-9"?) .22-250 version would have gone a long way toward making the .22-250 more amenable to a more rapid ROF.

The ROF the original barrel could not sustain was in the range of around 1rd/min or faster, as would be encountered in regular High Power Competition..

I have done some very preliminary testing of the 5.56 with Winchester 64gr Power Point bullets and 26.0gr of Varget out of a very new, just being initialized Stag Model 6 Super Varminter that was built up from a factory kit within the past month. I will be actively pursuing those HDY 62gr bullets for testing with a variation of this load. It has been putting pairs of them literally through one very small (just barely oval) hole at 110yd, and is the next testing project up on my shooting schedule, along with 50gr Nos BT loads spanning 26.0gr-27-0gr.

If timing is right, I may be able go down to my club range in Douglas (50mi) later today and find out if what I was seeing has any reliability.

Greg

 

[Potss]

Thanks CMH & supratt96 more great info on the WSSM. I'll be running whatever I get suppressed 100% of the time so I'm not super concerned about noise/blast. That is one of the major reasons I want a shorter barrel, 20in+ barrels with 7in+ suppressors are just way to long to hunt around here. Anyways on the magazines I've heard you can modify a 30 round AR mag to fit 10-12WSSM like shown in this thread and others: http://oa2.org/Forum/viewtopic.php?f=66&t=10073&start=25 Have either of you tried that?

Greg Langelius of course the more data the better! I will say that your experience sounds just like mine with CHF barrels and heating. I think that a nice cut rifled and relieved barrel might not exhibit the same flaws, but we shall see. I too was very interested in the LW's jacketed offering when it was annouced back in 2011. It was the precursor to the SJBS/Dracos in some ways. But I'd rather just have those instead now.

From the numbers I've seen around the web and ITT, it looks like from an 18in barrel the .224 WSSM would be around 3900fps with a 62gr projectile, while the .22CM would be around 3750. So if internet numbers, reloading software, and guestimation can be believed, it seems the WSSM does actually have a lead from shorter barrels. I was actually kind of hoping this wouldn't be the case since WSSM seems to have everything going against it except raw performance, whereas the .22CM has the brass, more mag capacity, easier to get parts, and so on. Just make the decision that much harder.

BUT as I say those are guistimates, if anyone has hard data on any of these calibers or similar ones from shorter barrels please post up!

 

[CMH]

I had two Olympic Arms mags and one or two PMAG's that cbass (OP in the link you provided) made. He was modifying them at the time, but I don't know if he still is or not.

 

[Potss]

Small world CMH, do you have the Pmags with the front cut off? How do they work for you?

On another note, I messed around in quickload quite a bit last night and it seems to be telling me the opposite of the numbers that are being reported here. Quickload seems to think that the .22-243 will be about 150fps faster than the .223WSSM, and I have no idea why.

 

[DP425]

Could always neck-down 6.5 SAUM. That has somewhere around 70gr of H2O case capacity right?

Building/buying an AR that can run it though... seems to be an issue. DPMS and Armalite discontinued their large frame magnums a few years back. Accuracy Systems apparently still builds them, but they are proud of their product...

And you'd still be left with buying one of their relatively expensive rifles, just so you could immediately rebarrel it.

 

[Potss]

Yeah that is why I put the limit at 22-06. I've spoken to multiple shops about the SAUM and WSM AR10s and the answer is always the same. With no more DPMS extractors, you are SOL when you bust one and you will bust one. Accuracy Systems has basically zero spare parts and charge a fortune. Plus we are so far into diminishing returns at this point in terms of performance from short barrels, the extra powder and barrel wear isn't worth it.

If I was going to neck down a series magnum I'd use a Falkor or Nemo because they have actual factory support for everything but the barrel. But again I don't see a point from such a short barrel. Good thought though.

 

[accurate_okie]

I used to have Win 70 in 243 WSSM and with 52gr h414 I could get a 55gr varmageddon to 3880fps and it was a devastating round for varmints. Traded it for an Oly Arms 243WSSM upper with, I believe, is a 20" barrel that I have yet to do anything with as I am collecting brass. You should be able to get this with a 223 WWSM without any issues.

WSSM's are brass killers when pushed hard so if you decide it whats you want you had better get on cabelas right now while they have 223 WSSM for cheap. I have been been searching for brass for years to get what i have now. This one of the only downsides of these rounds.