Can the absence of a bolt O ring cause FTFs?

[ryu_sekai]

I purchased a High Quality BCG from a very reputable dealer and the o-ring not installed when it came (separate little baggy). I thought the O-Ring was an extra so i did not install it and I did not take apart my Bolt before going to the range. When I got to the range, using several different brands of XM193 clones and a combo of Magpul mags and USGI mags I had a Fail to Feed about every 2 rounds. It would either not chamber a round (sliding on top over the round in mag) or it would only half chamber a round. After about 40 rounds of this I borrowed a friends Olympic arms BCG and did a 20 rd mag dump, NO Malfunctions. I also borrowed another friends RRA BCG and did another 20 rd mag dump, NO Malfunctions. I tried my bcg in his RRA and it seemed to run fine with out the 0- Ring installed. I called the dealer back and they told me to send the BCG in for inspection. Dealer called me back this morning and told me the BCG runs like a champ after several full auto Mag dumps.

Weapon used is a 10.5 MRP with Spike ST2 buffer and Sprinco Buffer spring (which runs like a champ when using other bcgs and is very accurate).

so, can a missing o ring cause all this?

 

[ajwcotton]

Re: Can the absence of a bolt O ring cause FTFs?

the o ring is there to help with extraction, did you check to make sure that the gas key was tight I had similar problems and it was because the gas key was not properly staked in.

 

[ryu_sekai]

Re: Can the absence of a bolt O ring cause FTFs?

I think my issue is the buffer and spring are too heavy, causing a short stroke... wish i would have realized that before sending of the BCG.

 

[Redmanss]

Re: Can the absence of a bolt O ring cause FTFs?

Do you mean a missing gas ring on the bolt, or a missing o ring on the extractor spring?

 

[ryu_sekai]

Re: Can the absence of a bolt O ring cause FTFs?

o ring spring extractor

 

[Redmanss]

Re: Can the absence of a bolt O ring cause FTFs?

Well, in that case I've never seen or heard of the lack of an extractor o ring causing feeding issues when extraction and ejection is still being performed properly. You got me...

I'd be looking somewhere other than a simple o ring, especially on a new extractor spring. I'm sure you already went through different magazines on it, but if you didn't try different types too (Pmag, milspec, SS, etc), give that a shot. Another direction to look is it could also be a possible break in or fit issue specifically with your rifle. Did the BCG have any unusual wear or rubbing signs on it? Would it stick or bind at all when operating it by hand? Final thing, although this is a long shot, is poor fit with your gas tube causing it to short stroke.

Just trying to throw a couple ideas out there. Best of luck with it.

 

[sobrbiker883]

Re: Can the absence of a bolt O ring cause FTFs?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ryu_sekai</div><div class="ubbcode-body">using several different brands of XM193 clones </div></div>

Sounds like your short stroking. A "d-fender" O-ring won't help or hurt feeding.

Did the weapon run with the above listed ammo with a different BCG (I'm suspecting not). Short stroking is usually gas related, but there are a few other things it could be.

 

[Tbag]

Re: Can the absence of a bolt O ring cause FTFs?

If I had to guess I'd try another buffer first, it may be a tad heavy. On that note did you try the single shot test and did the bolt lock back?

 

[ryu_sekai]

Re: Can the absence of a bolt O ring cause FTFs?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tbag</div><div class="ubbcode-body">If I had to guess I'd try another buffer first, it may be a tad heavy. On that note did you try the single shot test and did the bolt lock back? </div></div>

did not do that, i should have. i pretty sure its the heavy spring or buffer. the other bcg i ran were semi auto which is lighter and it ran like a champ

 

[Tbag]

Re: Can the absence of a bolt O ring cause FTFs?

Keep the spring in it and try another buffer.

 

[ryu_sekai]

Re: Can the absence of a bolt O ring cause FTFs?

ya i have a h buffer ill throw in next week.

thanks for the help guys