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Posted: 6/13/2009 12:56:47 AM EDT
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Please excuse what is probably a dumb question from a new English member, I'm sure that this subject has probably been done before, but here goes:
Unfortunately the iconic Black Rifle is pretty uncommon in the UK & hence there are relatively few resources & gunsmiths who know much about them. In February I bought an AR15 from one of the only 3 UK dealers I know of: basically it is a Tactical Solutions AR-22 LT .22lr dedicated upper married to a Sabre Defence XR15 lower. The barrel is 12.5" with a Whisper over-barrel moderator fitted. Using BDM 25rnd magazines From day one, I have had cycling problems using subsonic ammunition (CCI, Winchester & RWS are the only brands readily available to me): the occasional FTC & FTE, but mainly FTF (about 25% of rounds) - from what I can tell it seems to be short cycling & not cocking the hammer (it chambers a round, but the trigger doesn't set). It seems to run fine if I feed it on a diet of CCI Velocitor, but high velocity ammo is of no use to me as I'm using it exclusively for pest control on farms & equestrian centres (can't spook the horses). Having read all the posts I can find regarding this type of problem (most of which seem to relate specifically to Spikes ST22 uppers), I have polished the bolt carrier rails, back of the bolt (where it connects with the hammer) & top of the hammer in order to reduce frictional loses when the action cycles. I religiously strip & clean the rifle (no lube, just a toothbrush & air-line) at least every 100rnds & have stripped & cleaned all of the mags as well. None of which have made any difference. I mentioned to the guy who built it for me (unfortunately he's a 4-5hr drive away) about shortening the recoil spring (which is already only 4.25"), which he said was a definite no no. The other issue I have is that at 40-50yrds, the grouping it produces look like they came from a tightly choked shotgun! From inspecting the rounds which I have had to manually eject after a FTF, they all show signs of the sealing bands being partially deformed from loading, is this likely to be the culprit? My apologies for being rather long winded, but I thought the more information I could give, the better the likelihood of getting a solution. Any assistance you can give will be much appreciated. Kind regards, John. |
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Its a blowback bolt, and you're using low powered ammo. Stands to reason that you'll have to lighten the spring loads slighlty to make it work correctly with the ammo you're using, you just have to find the right ballance. Get the bolt spring too light, and then it might not want to close the chamber all the way.
Can you get replacement springs? If so, then yes, trimming a coil off at a time would be worth a try. Also try progressively trimming off one of the legs of the hammer spring 1/8" at a time, and see if that helps. Blackdog Machine has Lakeside spring kits , not sure if you can import? |
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Thanks for your reply, I was considering trying trimming the springs, but didn't want to without a spare on hand.
I have e.mailed both BDM & Spikes about the Lakeside Spring kits, but neither have responded. Due to our draconiam fire arms laws, AR15 components are notoriusly difficult to obtain in the UK & unfortunately most US suppliers don't seem to want to ship internationally. |
| Trim the springs, I fire subsonic target ammo all the time specifically sk target match and wolf target. I trimmed the spring to 7.5" and it works perfect without any FTE. If you trim the spring this short I would avoid firing higher power ammunition or you may get some OOB's. |
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Try Mark Bradley in the UK. He knows all things AR and currently builds .22 AR's among lot's of other more interesting stuff. He is the moderator on here on the UK Hometown Forum..........
...and there actually quite a few AR's in the UK, albeit anything other than .22 rimmie has to be built as a straight pull bolt action..Oh and I'm an old English member but it doesn't stop me asking dumb questions. 
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I've just managed to order a Lakeside Spring Kit from the very helpful Howard at JB Arms so at least now I'll be able to tinker with spring length etc without fear of rendering my AR useless. Incidentally, out of all the companies I contacted (inc Spikes, JP Rifles & BDM) regarding the spring kit, JB Arms were the only ones who had the courtesy to respond, I was quite surprised...
I did speak with Mark Bradley the other week, but unfortunately he wasn't taking in any further rifles to work on until his RFD licence was renewed. In the mean time, I've bitten the bullet (no pun intended) & returned my AR to Wayne at North West Custom Parts (who built it) to see if he can sort it out. Hopefully he wont have it too long! |
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