AR length of pull?

[red caddy]

Here's the problem: I recently finished a .458 SOCOM build. First time to the range the charging handle hit my nose in recoil. (not hard) With 300 Gr bullets, the recoil is moderate, the 600 Gr, @ 2200 FPS, Is a whole 'nother thing. (The 600's are very manageable in my Marlin 1895 45-70, 11 1/2 lbs all up, loaded. The not quite 7 lbs AR is a bit different, to say the least.

I need the easiest way to add about an inch, to an inch and a half, to the length of pull. I have heard that the AR-10 buffer tube is longer than the 6 inch M -forgery adjustable. Anybody know for sure?

I'm looking for something a bit more elegant than screwing a spacer and a shotgun recoil pad to the adjustable butt.

Yes, I'm a knuckle dragger, with the AR I feel like a hunch back on a skateboard. With body armor on, my MI-A is too short...

Let the games begin.

Paul.

[FrankenMauser]

Vltor A5 Recoil System Extension, if you want to stay with the adjustable stock.

If not... grab an A2 stock, or one of the various fixed stocks with additional length of pull (or the option for extensions, like the Magpul MOE Rifle stock).

I run a Magpul MOE Rifle stock with the thickest extension on my ".458 SOCOM". It isn't for the recoil, as most people assume. It's just for the LoP.

[marine6680]

What stock is on it now?

Some are longer than others.

My Magpul SL stock is an inch longer than my BCM stock.

The Vltor system is longer than the standard tube as well.

[red caddy]

Thanks Franken mauser, I hit flea bay and scored a Vltor A5 lower extention cheap.

I'll have it by Friday this week. It's advertised as being 7 3/4 inches long, my M-4 is 6 inches. I'm hoping my spring and buffer will continue to work, but I'm unsure of the inside length of the extended tube,

No worries, I can turn up a nylon spacer if I need to. I will add a limbsaver shotgun pad and a kydex cheek rest to the M-4 butt piece (that damn checkered plastic part just chews holes in my t shirt, and the blood bag) Most of the time, it's way too hot down here for heavy shirts or shooting vests.

Marine 6680, The tube on it now is the M-4 Anderson that I found in my parts pile, when I was casting about for a "quickie" lower to drop the SOTA upper on, just to get it to the range.

I do a fair amount of "upgrading" work, in addition to custom builds, so I have a big box of orphan and cast off stuff that I mix and match with.

I'll post after the next range session with some 600 Grainers.

Thanks very much for the help.

Paul

[FrankenMauser]

Definitely check for gas key strike, before assembly and testing. They're said to need a special extended buffer.
I should have said something more clear about that in my previous post.
I'm sorry if that causes any inconvenience.

[marine6680]

Yes... The extra length mean you need the associated buffer and spring, if you don't use them, it will damage the rifle.

[stagpanther]

Don't know if this helps any--just a suggestion.

I built a 458 socom last year--and at first I had some issues shooting it (it operates flawlessly) but it has now emerged as great performer and I really enjoy shooting it. I generally stick within 300 to 400 gr bullets as that seems to be the sweet zone for the combination of energy and range effectiveness.

With the warmer loads I at first experienced the same you have--when you say the charging handle hit you in the nose--I assume you mean upon recoil the gun did some muzzle flip or push back hitting you--and not literally the charging handle unlocking and flying back to hit you?

Anyway, what I eventually figured out was that the the rifle had to be fired like a conventional big-bore bolt-gun--meaning a relatively loose grip (like I do with other smaller AR calibers when shooting from a rest) was asking for trouble. Although targeting is a more challenging, I firmly grip the rail and pull back into the shoulder to provide solid resistance to the recoil forces--and a good brake/compenasator helps too. No hits--and accuracy actually improved over "limp-gripping." You're still going to end up with some shoulder bruises after a session with hot loads though. It can be also rather intimidating having that heck of a bang and kick out of an AR 15.

PS--if you reload try some FTX's driven by A 1680--I've found that to be a great combination in my 458 socom.

[zukiphile]

I'm a bit late but the Choate E2 has a LOP 3/4 of an inch greater than an A2. I like it for prone, but not standing.

https://www.midwayusa.com/product/10...ynthetic-black

[Mobuck]

If you switch to a regular scope(choose one with a fairly short eye relief), the ocular will contact your forehead before the CH hits your nose.

[red caddy]

Hey, thanks very much for the continuing input.

Franken-Mauser, I'm not familiar with the term "gas key strike", school please.

Marine6680, My upper functions fine with the A2 length spring and buffer, if that combination proves to be too short, a tubular spacer, returning the inside depth of the extender to the A2 length, should work, as long as the buffer can't slide inside the spacer and travel with it. (solid Delrin plug?) What say you?

Zukiphile, This thumper will not see much prone position, I'm a believer in shooting sticks, (at my age, it's more of a dual purpose walking stick, lol) usually from the sitting position with my "reach out and touch 'em" guns.

In my .458 SOCOM the heavier the bullet, the shorter the effective range. Pig's, at less than 200 yards is the most likely of victims.

I have other, better suited, rifles for reaching out across the sod and beanfields, (45-70, 45-90) this one is a "close in " HAMMER. (I named her "MJOLINAR" after Thor's hammer)

Mobuck, I've been using a Propoint red dot for break in but will likely change to a MER pistol scope in the swamp. (2-6 X 44 to 50 objective) most shots in my part of the swamp are running snap shots, so I'm going to adjust the balance and LOP to swing more like my pet 20 gage o/u but still be comfortable from sticks. BTW, a 20 Ga. slug will make a pig DRT, dependent on shot placement.

Stagpanther, I have always been a proponent of "hard hold" Many Gunnery Sargent's and Master Chief's had a hand in my raising. Way too many years in High Power matches for me to be bothered by recoil bite. As I age out, it does get more bothersome, though.

Thanks again guy's

Paul

[zukiphile]

Franken-Mauser, I'm not familiar with the term "gas key strike", school please.

He is referring to use of a too short buffer that allows the BCG to travel too far back and damage the lower when it is hit by the gas key.

Zukiphile, This thumper will not see much prone position...

I only meant to illustrate the length of the Choate. I'm 6'2", and it's a bit more than I like for standing.

[marine6680]

I don't recall ever having an issue or single instance of heavy recoil causing me to get hit with a scope or part of the firearm... A change in technique may be a quick and cheap solution.


But the VLTOR system is longer, so that is why you need the buffer and spring from them.

The buffer actually hits the rear the buffer tube, and prevents further rearward travel of the BCG... Using a standard buffer with the VLTOR means the BCG can move farther to the rear, and impact the receiver, causing damage.

You could make a plug to fit inside the buffer tube to take up the extra space... Seems getting the new spring and buffer would be easier.

[FrankenMauser]

He is referring to use of a too short buffer that allows the BCG to travel too far back and damage the lower when it is hit by the gas key.

That. ^^^

I actually check for gas key strike on every build. I've never found a combination of "standard" parts that was even close. But it doesn't hurt to check before moving on with lower assembly...

[red caddy]

Marine6680, you may be right, but, I have a pair of Winchester mod. 70's, one in .458 Lott and the other a 416 Rigby, that have marked several shooters, despite an admonition to "take a deep seat and a tight rein " prior to yelling "outside"
Neither has ever marked me, yet.

Zukiphile, I have never personally encountered a buffer contacting the end of the buffer tube. As was said, it could happen, and should be checked. And I will.

Franken Mauser, how do you check for gas key strike? I would think that manually forcing the BCG back until coil bind of the buffer spring or buffer contact with the end of the buffer tube halted rearward travel of the BCG would be indicative of a problem or lack of one. This .458 SOCOM is the heaviest recoiling AR in my stable and there is no evidence of any contact on the A2 buffer or the end of the 6 inch buffer tube, despite several rounds of 600 Grain @ 1950 FPS. To be sure, recoil of the 600 grain loads is not for the faint of heart, but it's not truly vicious, that term is reserved for the big Africans...

I'll know quite a bit more when I have the extended tube in hand.

Thanks, Paul

[stagpanther]

You would easily see carrier strike by the buffer being too short--the threads of the buffer tube collar would show impact distortion from the carrier. I have a fairly light socom build too--I agree when you light off a round with over a ton of muzzle energy it's going to kick back.

[mavracer]

600 Grain @ 1950 FPS

??? From a 458 SOCOM in an AR15. That's faster than the factory 400s and at over 5k KE would be over the design limits of the AR platform.

[stagpanther]

I kinda got stumped myself at the first 600 grs at 2200 fps inside the 458 socom case seems like a mighty hot load That's up there in big 5 dangerous game territory.

[FrankenMauser]

Drop the recoil buffer in the tube. Insert the bolt carrier on top of it. If the gas key hits the tube or the lower receiver, something's wrong.

(No spring necessary, since the buffer is supposed to act as the maximum travel stop at full compression of the spring.)

If the Vltor tube is too long, but the same inside diameter as standard tubes, a spacer should correct the problem and allow use of the current buffer and spring.

[Nanuk]

?? From a 458 SOCOM in an AR15. That's faster than the factory 400s and at over 5k KE would be over the design limits of the AR platform.

Me too, that is what a 300 does with a very hot load.

https://load-data.nosler.com/load-data/458-socom/

[red caddy]

Hey, I just caught my typo 1250 FPS NOT 1950. Sorry about that, those would be impressive numbers, but I'm not that crazy. My350 gr. loads calculate to 1800 but I have yet to get them across my chrony.

I gleen my starting and max loads from 458 SOCOM .com and a couple PM'ed from a member on The firing line.com. (he was hesitant to post them on an open forum, as am I)

The 600 Gr'ers may not be reaching the calculated FPS, no signs of pressure yet, nice round primers, but the blast is fierce and the recoil is memorable. I just couldn't wait to try them.

I originally bought them for my Marlin 1895 45-70, very accurate at 1780 FPS on my chrony . The 45-70 will drive a 260 grain jacketed HP upwards of 2700 FPS, but accuracy suffers from what the heavier bullets will do.

A lot of people I know tend to treat the SOCOM like a 45-70 short. The AR platform must be tougher than we think 'cause you don't hear of many KA-BOOMS.

Crawling back under my rock now, Paul

[red caddy]

I got the commercial extension tube on Thurs. Inside measurement is 7.365" hit the gun show today in Tampa for several Commercial stocks. (converting all my AR's to extended length commercial, couldn't find Mill-spec extended length buffer tubes. Tubes are $12.00 stocks are $15.00)

I slammed one together and gained 1.5 " LOP. A limbsaver shotgun pad will add another 1/2 inch. A set of ex-high QD rings and I'm RTR. (The stocks I found have a snap on cheek piece)Handling is much improved, still have to work on the swing and balance thing, and make a couple Delrin spring spacers.

As always, thanks for the help.

Paul