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[Ian02]

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[Evil Bert]

looks decent enough. the only difference between a 14.5 and 16" carbine gas system is that the 16" will recoil more violently as there is more gas in the system due to the longer length of the barrel from the gas port to the end of the barrel. On a standard M4 14.5" carbine barrel, the distance is about 7.5" with a standard A2 flash suppressor. On a 16" carbine, the distance is increased to about 9.5" when means the bullet takes longer to exit the barrel and allows for more gas to traverse into the action. More gas means more pressure. More pressure means greater recoil. It is still manageable, but not as desired.

As far as the buffer is concerned, the standard H buffer should work just fine for you with the M16 bolt. You should change anything on the rifle unless you need to for a specific reason. Shoot the rifle first and go through the break in period of about 300 rounds. Then based on the performance decide if you need to change anything out. The point of the heavier buffers, as I understand it, was to modify the cyclic rate of the select fire M4 in order to increase reliability. Being that your rifle is not a select fire, the standard carbine buffer should be just fine. Should being the operative word.

[Hmac]

I wouldn't be a bit surprised if either of those carbines would cycle your ammo just fine with an H2 buffer, and soften your recoil impulse to boot.

[Eric D.]

Tweaking buffer weights can benefit any rifle, select fire or not.

The carrier key staking leaves a bit to be desired. Its also important to realize that MPI really doesn't mean anything without an HP test first.

[Ian02]

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[Evil Bert]

I wouldn't be a bit surprised if either of those carbines would cycle your ammo just fine with an H2 buffer, and soften your recoil impulse to boot.


True as it couldn't hurt to try the different weights, but my point was that if he shoots it and breaks it in, and he is perfectly fine with the recoil impulse, especially since he is used to 16" and now has a 14.5, which should in and of itself recoil softer than what he is used to, then no need to change anything.

Now if he is really interested in softening the recoil with a dramatic result and possibly increasing reliability, then the OP should look at buying the VLTOR A5 recoil system. He certainly cannot go wrong with that.

[Evil Bert]

Would the HP test be marked somehow? I noticed it on the chart but didn't know how I'd know if mine was.


First you need to understand what the HPT (High Pressure Test) consists of. It is simply test firing the weapon and then inspecting it for damage, in a nutshell.

If your rifle smelled like it had been fired and you bought it brand new, then likely it was HPT. Most firearms are HPT in some way or another as most manufacturers test fire the gun prior to shipping it. Oh and HPT should be done prior to the MPT (Magnetic Particle Test) which will show any fractures within the surface of the bolt.

Again I am summarizing here. so if I missed something please do not jump down my throat. :D

[5pins]

High pressure testing is more than just test firing. It involves testing the rifle with the M197 high pressure test cartridge. The barrel and bolt are then magnetically inspected for any defects. If your rifle was high pressure tested then it should be marked HPT on the bolt and barrel.

[RogerinTPA]

Sorry, but your gas key is not properly staked.

[DacoRoman]

Sorry, but your gas key is not properly staked.

You beat me to it.

Send the BCG back to them for a proper staking of that gas key.

[jdodd]

The staking certainly isn't "troglodyte with a hammer" status like a colt / bcm etc. but looks good to me.

:p

-J

[DacoRoman]

The staking certainly isn't "troglodyte with a hammer" status like a colt / bcm etc. but looks good to me.

:p

-J

That's not staking, those are simply some dimples placed in the gas key. Those screws are free to come loose as there is no anchoring point to the gas key whatsoever. Do a search on here and learn what proper staking looks like.

[Ian02]

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[Evil Bert]

This is what a properly staked gas key should look like. Notice the key actually comes over the screws, etc.

http://www.gandrtactical.com/images/archive/Colt/Gas%20key%20stake%20job.jpg

[jdodd]

Edit: repost in a minute or two

[stifled]

The staking certainly isn't "troglodyte with a hammer" status like a colt / bcm etc. but looks good to me.

:p

-J

I'd say they moved about half the material they should for me to be comfortable with it. My first AR-15 was a Stag and was staked similarly. The bolts didn't loosen in the ~1500 rounds I shot out of it before becoming aware of the issue, but that doesn't mean everyone is so lucky. MOACKS to the rescue!

[Icculus]

In addition to that, show me somewhere where the bolts backed out from an improperly staked key.

Seen it twice in person. Once on a BM and once on a DPMS. Both times at the range and both times choked the rifle

[meausoc]

I know that Stags are not at the top of the chart but it looks like they are making some positive changes in regards to the 1/7 twist, M4 feed ramps, and staking the bolt carrier. I have two builds with STAG lowers and LMT uppers bought from G&R and so far no issues.

[Eric D.]

IIRC NATO proof loads run about 30% higher pressure than a 5.56 cartridge.


High pressure testing is more than just test firing. It involves testing the rifle with the M197 high pressure test cartridge. The barrel and bolt are then magnetically inspected for any defects. If your rifle was high pressure tested then it should be marked HPT on the bolt and barrel.

[Iraqgunz]

No, it isn't staked properly. Yes, I have personally seen more than a few carrier keys loosen from improper staking. Whether or not you choose to believe that is irrelevant.

It's your weapon. Listen to what you are being told or don't.


Metal from the carrier is touching the bolts in 2 locations per bolt. Tell me why you don't think that is sufficient. In addition to that, show me somewhere where the bolts backed out from an improperly staked key.

[Ian02]

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[fdxpilot]

I know that Stags are not at the top of the chart but it looks like they are making some positive changes in regards to the 1/7 twist, M4 feed ramps, and staking the bolt carrier. I have two builds with STAG lowers and LMT uppers bought from G&R and so far no issues.

Unfortunately, the OP got his upper from the Stag LE line. They are still selling the same mediocre equipment to regular consumers. They are at least starting to realize that M4 ramps are needed on some weapons, such as those chambered in 6.8SPC. (Of course, they didn't do that till a poll on 68forums said over 40% of Stag owners had feeding problems.)

[Wolf Spyder]

Ian02,

Thank you for your post. The photos are good, and very informative. Have fun and enjoy your new toy, err I mean tool. When you have put a few hundred or a thousand rounds down range, update us. Let us know what going on with the rifle.

[Ian02]

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[Ian02]

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