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Posted: 6/4/2014 9:09:36 AM EDT
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Been learning and gleaning a lot of knowledge here for a a while. For that, thanks to those that provide great info on these platforms. Prior to getting into the AR platform (other than the service...long ago) I really only worked with pistols and bolt action rifles. Well, like potato chips, you can't just have one! LOL
After owning a true 16" M4 clone carbine (commercial) I decided to build my first one. Only have the upper completed so far and it pins on my current lower perfectly. According to my wallet  here's the list of parts.
upper and lower (ordered together) AeroP. (forged x15 set) Diamondhead VRS-T 13.5" Rainier 16" select barrel (middy) BCM mod 4 medium CH TR Enabling BCG misc. boiler plate FA and dust cover Diamonhead polymer forward and rear BUIS PWS FSC556 comp lowpro gas block & spikes nitrided gas tube Build was 99% easy except for the PWS which I used the shims included in lieu of a crush washer. Took about an extra 15 minutes to get the stack right, but worked perfectly. Got it out last Monday and ran 70 rounds thru it. (50 62 gr. 855 and 20 PMC 55 gr.) First 5 rounds @ 25 yrds to get it on paper. (my bore sighting of the BUIS was damn close to zeroed) Rest of the rounds @ 100 yrds. (damn old eye on irons @ 100 yrds was interesting.....8" target looked like a flea on top if my front post  )
The upper played nice with my carbine lower and was able to keep a 4" grouping with the Irons. The PWS worked excellent and to my ears, was no louder than the bird cage on my 16" carbine. The reduction of muzzle rise was very good and the recoil impulse was straight back. Only had 3 hick ups and that was with the 855 62 gr. three separate mag loadings had a bolt lock back with rounds still in the mag. Dropped the bolt release and back in business. Not sure if the middy gas system wants a different buffer. did cycle fast with the hotter 855. Worked flawlessly with the 55 gr PMC. Not going to put much stock on this until I get a few more rounds thru it to get everything broken in a bit. If you have any hints though, share away. Did this on different mags and only with the 855 and only 3 times. (pmags, usgi, steel which all functioned perfectly on the PMC) All rounds extracted and ejected perfectly with no signs of being abused by over gassing or timing issues. So no big deal. Oh, and a side note, the Rainier barrel cleans up real fast and easy as advertised. This barrel has potential. I know pics or it didn't happen...well us old dial phone guys that have a cheap flip phone....yada, yada yada doesn't have current access to all that tech. LOL So, flamethrowers away... 
I'll update as I can and when I put the lower together. Based on the "hiccups", I will have to think about the spring buffer combo for the new lower. Oh, and I'm robbing the Hyperfire 24 out of the current lower to use in the AeroP lower and put back the milspec FCG in the old lower. Like that trigger a lot! Feels very much like my Savage accutriggers on my long range bolt guns. |
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Hi Cap, nice build. I can only guess why the bolt hold open was tripped with rounds still in the magazine. The follower in the magazine trips the bolt catch for the bolt hold open. How is the spring tension on the bolt catch when you manipulate it by hand? Nice and firm? Are you sure you have the correct spring and the buffer installed for the catch? Is it sticky or does it get hung up, or does it function smoothly? It might just need a little cleaning. I know what you mean about the flea on your sight post. It's time for a nice scope. Good luck with it, someone around here might know the solution. I have not had that problem myself. Good luck. -W
ETA: I did have to use emery cloth to sand the finish off a bolt catch on a build to get it to operate smoothly. |
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Thanks wools, at my age and OCD nature (old A&P) I wanted to build something nice to my specs and desires. May not be the budget PSA build, but what the hell, I earned the right to do it my way. LOL
The bolt release is all good, smooth and good spring tension. Works flawlessly with the carbine length gas 16" upper and all mags tried with this new upper. Also worked without a hiccup with the lower power PMC bronze 55 gr. The only thing I could think of was the buffer & spring in the existing lower that was factory matched to the carbine length gas on it's upper. But hell, I'm still learning these DI systems over bolt actions. LOL Like I said, it ran faster with the 5.56 855 rounds, but showed no signs of abuse to the brass. It was only three times, so I'm not gonna rush into assumptions until I get a few more rounds down the pipe. I just want to make sure I give the lower the correct spring/buffer combo for this middy gas system. Testing is so much fun....aw heck, I have to go shot my rifle some more!
Scope is in the works. Decisions, decisions.....with all my long range desires dealt with on my bolt guns, I was thinking about a 1x4 or 1x6 for this. That should play nice out to 500 yrds if needed. Not to cumbersome, easy and some of the illuminated reticle units have my interest...especially with old eyes. So many choices! LOL
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I think the standard is a light barrel gets a standard buffer, a M4 barrel gets a H buffer and a heavy barrel uses a H2 buffer. I'm sure some will disagree with me, but I think that's how they come from the factory. That would be for a 14.5 or 16" barrel with a carbine gas system. I'm sure there's a multitude of combinations. -W
ETA: hopefully, someone with mid length gas system experience will share their opinion. ETA: in my first post, when I asked about the catch buffer and spring, I meant the bolt catch buffer and spring, not the stock buffer and action spring. -W |
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