SBR (seekins pistol) AR15 cycling issues.

[DeauxJoe]

Hey all, sorry as I know this will be a vague post. I'm just looking for an idea because I'm not sure were to look for starters. This is my first experience with SBR's. I bought a Seekins pistol and got it last Friday. Took it out to try it out and it will not cycle at all. I fired it and it is acting exactly like an AR with an adjustable gas black with on the single shot setting. It fires and seem to make no effort to cycle, if I manually cycle it, the pistol will fire again. I contacted the guy I bought it from and he said he had "no idea". Anyone with any experience with these I would great appreciate a suggestion as to what to look at. Thank ya'll!!

Link to thread where I bought it:
http://www.snipershide.com/shooting/showthread.php?t=177708&highlight=seekins+pistol

 

[Jaytrigger]

Is your gas system all hooked up right? Sounds like the gas isnt coming through the pipe to cycle the bolt back. Adjust you gas block to open it up a bit.

 

[ORD]

Well...let's try some of the basics first.

1) what kind of ammo were you using?

2) was the pistol properly cleaned, lubricated, etc. before shooting with it?

3) are you sure that the gas block is installed properly on the barrel (and likewise...that the gas tube is properly installed on the block, going into the upper without binding, has no bends, kinks, damage anywhere, etc.)? Also, what size does the gas port in the barrel measure?

4) what do you mean by "makes no effort to cycle"? Does that mean that the bolt doesn't unlock/the carrier doesn't move AT ALL or moves only slightly?

 

[Nutro]

Hmm it sounds like it's configured exactly like my Seekins setup. Mine short stroked once. Here is my guess.

I pulled my hand guard and loosened the gas block screws. Moved the gas block (More like barely shifted it) and tightened it again. It has worked ever since.

OR

Open the adjustable gas block port all the way then bring her back 1-1/4 turns and lock it down.

 

[DeauxJoe]

Jaytrigger : I'll have to break it apart and check.

 

[DeauxJoe]

ORD:

Lake city green tip

I took it out the box and put a mag in it. So I guess it could be a packing grease issue. But I bought it second hand and when I opened the rife up I saw no signs of excessive carbon or grease.

That's where I was thinking my problem lies I just didn't want to start messing with it without a second opinion lol. I will get it apart tomorrow and check that out.

The bolt doesn't appear to even unlock from the carrier. I can detect no movement in the bolt. I see some gas coming from the breach but that's it.

 

[DeauxJoe]

Nutro:
Thanks when I break it down I will check that out.

 

[DeauxJoe]

Update:
I took the hand guard off and tried just moving the gas block around a little. That did not work. I shot a few more rounds out of it and i am getting carbon on the barrel in front and behind the barrel. That says I'm loosing a lot of pressure from that spot. Any suggestions for that?

 

[ORD]

Its not ammo or fouling or grease from the sounds of what you have updated us on...the problems are in your gas system somewhere.

A small amount of residue/powder/carbon is normal around the block, but what you are describing is likely a misaligned gas block or a block that isn't getting a good seal/fit on the barrel (at least in part). You have a set-screw gas block on that barrel from the info contained in the "For Sale" link you posted, but I don't know if Rainier's "Match" barrels are dimpled for the set screw blocks or not. It could be that your block isn't seating/sealing properly around the gas port, is misaligned and the gas port isn't getting sufficient gas to cycle the action, your gas tube could be installed incorrectly, damaged, plugged up, the incorrect length (easy to check just by looking in the upper receiver area with the carrier removed), etc. Is the block loose or does it move with some force without loosening the set screws? If that's the case, then some rocksett may be in order (or red loctite) on the set screws...assuming the barrel is properly setup for a set screw block to begin with...and torque them down to around 65in/lbs (better check with Rainier on the exact specs as I can't honestly recall if that is what they use, but others with the same/similar design are in that range).

Again...break it down, clean it up, check the individual components of your gas system (and barrel) for the issues above, and try it again.

 

[chakup]

I'm going to guess it's either A) Gas block - either misaligned or boogered. B) Carrier Key. last thing I'd look at would be make sure the gas port is proper size

 

[stingrayguy]

I had a rifle do the same thing. Turns out, mine had a tiny chip in one of the trigger parts, cost me about $6.50 to fix.... worth a look?

 

[LRRPF52]

Remove the gas block and measure the gas port with calipers.

What is the gas block made of? Aluminum or steel? If Aluminum, it needs to be replaced. Aluminum gas blocks are only ok for Rifle-Length Gas Systems, and I still steer clear of them entirely myself.

If the gas block is steel, ensure it is aligned with the port when installed. Backed up all the way to the shoulder on the barrel is not aligned usually.

What buffer weight is in the extension tube?

What recoil spring (length)?

Keep in mind the AR15 was never meant to run with this gas system and barrel length. The original 10" gun was the Colt Model 607, then the XM177E1, both of which were found to be unreliable due to dwell-time and port pressure issues, so the XM177E2 was developed with an 11.5" barrel and retained the 4.5" moderator with baffles to help increase dwell time/back pressure.

The next military carbine was the Colt Model 653 with a 14.5" barrel, which is the most ideal barrel length and gas system length for the Commando series of AR15's. SOCOM has re-learned the hard way with the Mk.18 CQBR 10.3" barrels that those guns just don't have the reliability record of a rifle or even 14.5" M4, especially when it comes to parts wear.

In short, the 10"/CLGS guns are on the extreme edge of reliable operating parameters, and those parameters are very narrow with 5.56 NATO.

 

[rpk762]

I do not know about the standard AR-15 handgun but I have an Arm pistol and I just changed powders and I was able to get it to function 100% of the time. It never worked with factory ammo. I went with a faster powder that what is normally used in 223. These rounds are not to be used in a AR.

 

[DeauxJoe]

Well I have tried several times to readjust the gas block and I am seeing no improvement. Next step will be to disassemble the gas system and see if there are any obvious issues. I will keep you guys posted. Thank ya'll so far for all the help.