12" Ejection issues Fixed with H2 Buffer

[Bearcatrp]

[VASCAR2]

Which 12” barrel are you using? Ballistic Advantage 12” 6.5 Grendel barrels were having function issues because they used a smaller diameter gas port. BA assumed most people would use a suppressor which increases the gas pressure. Some forum members were having inadequate gas to function the upper without a suppressor. If there is insufficient gas the bolt carrier might not travel far enough to the rear to fully feed the top cartridge out of the mag. This is commonly called short stroke. Some times with insufficient gas the timing is off enough to encounter the failure to feed which you described.

The real problem is it is hard to tell the difference as to whether a rifle is over or under gassed because the failures can be similar. A bolt carrier moving to fast can still cause failure to feed because the top round doen’t come up fast enough in the mag to be fed into the chamber.

Faulty mags or extractor/ejector can cause feeding issue. When you get your upper back if you still encounter problems it is helpful to give the brand of barrel, gas system length (pistol, carbine, intermediate or rifle) and buffer tube length, spring and buffer used. Also helps to know specific magazine brand and capacity causing failure.

[Bearcatrp]

The barrel is a faxon match 12.5 inch barrel. Picked it up here.... http://sulzerfirearms.com/12-5-6-5-g...omplete-upper/. Magazine is a C products.

[VASCAR2]

Hopefully Sulzer/Faxon will get this upper/barrel sorted out.

[LRRPF52]

What type of malfunction are you having?

Sounds like a failure to feed.

Does the bolt override the cartridge, or is the bolt still behind the case head when you experience the malfunction?

[Bearcatrp]

Have 10 rounds in mag. 1st couple fire and eject, then about the fourth round, the brass ejects but the next round jams at an angle, enough to dent the round. Bolt is against the live round. Have read C magazines have issues but could be the buffer, just not sure though.

[Lastrites]

C product mag may need the front lip of the mag filed down a touch and you may benefit from taking the mags a part to clean and remove excessive flashing or other potential hang ups.

[tango29]

Failure to feed/eject

Try the following to fix the issue

Try the following things to see if you fix your FTE issue.

1. Check that the gas block hole is lined up with the gas port on the barrel
2. Check that gas block and gas tube is lined up correctly with receiver
3. Polish the extractor claw it may be sharp and sometimes sharp edges
will hold the case too long not releasing it to eject properly.
4. Change the buffer spring could be to light or heavy
5. Change the buffer could be to light or heavy
6. Try different magazies
7. try taking rubber o-ring off the extractor spring
8. try taking a coil off extractor spring
9. http://www.youtube.com/watch?v=fuCinEiYuIQ
10. http://www.youtube.com/watch?v=kYm5UjojDMU

[Bearcatrp]

Thanks for your help. But ejection is not the issue. Feeding is after a couple shots fired. It will eject fired brass, then jam. Have to pull back charging handle to get the unfired round sitting cockeyed. I wasn’t aware until after I started this post that the type of magazine I bought has issues. Am thinking of getting a different mag that is known to work. If does the same thing, change out buffer for a heavier one. Sulzar firearms still has the upper to test since grouping at 50 yards was horrible with commercial and reloads. Read somewhere that faxon had a batch of bad barrels that shipped to customers so hoping it’s verified and replaced.

[Bearcatrp]

Got it back. They tore it apart, back together and fired. They found no issues. Sent me a pic of good groups. They used a sled bed. Can’t go shoot until I heal up from back surgery and doc clears me. In the mean time, ordered a couple boxes of ammo from AA plus a E lander mag to try. Am wondering if I should order a H2 buffer to have on hand in the event I still get jams when shooting the 120 grain nosler I ordered from AA. Should I?

[LRRPF52]

Have 10 rounds in mag. 1st couple fire and eject, then about the fourth round, the brass ejects but the next round jams at an angle, enough to dent the round. Bolt is against the live round. Have read C magazines have issues but could be the buffer, just not sure though.

This is called a bolt-over-base malfunction, usually caused by excessive cyclic rate.

I would recommend first trying a heavier buffer as a rate reducer.

The next option is to use adjustable gas.

It can also be caused by mags that are binding up a little, so disassembling and cleaning the mags can help.

With CLGS and certain port sizes, it's usually excessive cyclic rate though.

My 12" Faxon barreled Grendel pistol is very well behaved using the Maxim Defense PDW brace with its own tiny buffer (standard carbine weight at 2.9oz, but much shorter) and a very powerful recoil spring.

It has not choked once so far, and is very positive in cycling. The spring seems to be the main contributor to that, plus the correct gas port diameter.

[Bearcatrp]

Is a H2 better to get to replace my standard carbine buffer? If I had the bucks, would get the brace you have.

[grayfox]

I'm using "H2"'s... spikes T2 or a Kaw valley T2, they seem to have less sloshing inside the buffer... nice and solid.

[biodsl]

This is called a bolt-over-base malfunction, usually caused by excessive cyclic rate.

I would recommend first trying a heavier buffer as a rate reducer.

The next option is to use adjustable gas.

It can also be caused by mags that are binding up a little, so disassembling and cleaning the mags can help.

With CLGS and certain port sizes, it's usually excessive cyclic rate though.

I have this condition using a 17-round E-Lander mag I have. Shooting a 16" AA Lite barrel with a JP SCS carbine set up. The malfunction does not occur with my 10 round ASC mags.

[Bearcatrp]

I see some H2 buffers are 4 oz and some 4.6 oz. coming from a standard carbine buffer, which one?