Armory Sponsor
Posted: 2/12/2012 3:36:59 PM EDT
|
Hey guys, I was wondering if anyone might be able to help me out with tuning my .22 upper. I've been through all of the tuning threads a few times over. Thanks to those threads, I've almost got it running full auto and was just looking for some insight from the experts.
Iterations that I have already gone through: 1. Stock upper - ran fine in semi except a few ejection problems 2. Dropped the anti-bounce parts and trip in. - Same experience in semi 3. Put it on a F/A lower. Got hammer follow / bolt bounce even with the weight and ball detent. 4. Added uncut Lakeside spring - got short stroking and the spring was so strong I got a lot of misfeeds even when releasing the charging handle on the first shot. 5. Cut the spring a bit x2 - ran a lot better each time but still was getting some hangups on chambering. 6. Cut the spring some more - runs awesome and seems like it's right on the edge of running all the time except I'm still getting a few ejection problems (feeding problems and bolt bounce are 100% eliminated in the 350 rounds that I've put through it like this) When I get the ejection problem (approx. 1-3 per magazine) the gun fires, strips the next round from the mag and gets it most of the way into the chamber, and closes on the ejected round with the primer sticking out. I think that I've got the spring weight close for it to run, but thought I'd ask to see if that may be a problem here. I know these can be near to impossible to tweak online with a description but I thought I'd ask in the event that someone else was having a similar problem. Is it possible that the spring is still a bit too stiff and the bolt isn't coming back far enough for a proper ejection? I'm a little hesitant to cut more since it's almost as short as the stock spring, but on the other hand, it's been running better and better the shorter that I have cut it. I've tried Federal Bulk pack and CCI Stingers. Had a bit better luck with the Stingers, but still having a few issues. Thanks in advance for any help or ideas! Crossposted in the Spikes industry forum since its an ST-22 and there doesn't seem to be lot of overlap in the two sub-forums. |
|
can you try other brands of ammo ? did you try with the original ciener spring ? it takes time to fine tune them. I had to go back to the original pieces and try different brands of ammo. I had good results with cci standard velocity.
polish the chamber feed ramp too. It will help a lot. |
|
With the conversion bolt installed, pull back on the charging handle. Can you see the conversion frame move at all? If you push back even further on the conversion bolt with your finger - further than the charging handle can pull it, do you see the conversion frame move at all?
If so, you need to find some way to shim or lock the conversion assembly into the upper so that it DOES NOT MOVE. Movement robs your 22 conversion bolt of the energy it needs to cycle reliably and repeatably. I believe the reason Rick Kuehl's uppers achieved such a good reputation for FA function was that his dedicated uppers locked everything down tight, which has not been the behavior I've observed in random uppers, especially those with problems. Try the CMMG locking chamber adapter. |
|
Is this a dedicated Upper or Drop in kit with 5.56/.223 chamber adapter? I'll assume dedicated.
Who made your bolt? CMMG or Spikes? I'm going to guess it might be a Spikes because you are using the "ball detent spring" that spikes already drilled the holes for. Ejection problems are usually caused by lack of back pressure from weak ammo, but you are using CCI Stingers which I believe are the 2nd hottest 22LR round at about 1650fps, the Aguila Super Max ammo is 1750fps. Anyway the more powerful ammo usually eliminates this issue. The other way to increase back pressure is to use a Suppressor (silencer) or a Carlson Comp Thruster (I haven't gotten a thruster yet but all the reviews seem good) and aparantly Carlson is one of the best suppressor (non-silencers) designers out there. My experiences, I had a lot of issues with the Spikes Bolt both drop in and dedicated upper. Would work decent on semi but not very well on full auto. Also suggest not using the ball detent, it's really not needed if you are using a lake side spring and the anti bounce weight. You may think you are having bolt bounce but it's probably just short stroking light primer strikes. I built a dedicated upper using a CMMG bolt, but a spikes barrel and collar adapter (which has to be grinded on where the bolt slide hooks around it) has ran almost 100% with using CCI stingers and Agulia super max ammo until recently when I found out that the Anti-Bounce weight can deform and cause problems after 3-4k rounds. Just file the burr off the anti-bounce weight and you are good to go LOL |
Armory Sponsor