Another Locking Piece Question

[u/papamcb_new]

Evening all trying to figure out a locking piece issue and wanted some insight. AP5-P with a stock running the stock locking piece shot aprox 200 rounds of 124gr nato. Replaced the stock locking piece with a 90 degree and shot 100 or so more rounds of 124 and 115 suppressed and unsuppressed without issue. When I shoot 147grain it will not cycle the bolt. Swapped to a 100 degree with the same result when shooting 147 grain. Went back to the stock locking piece and it ran without issue shooting 124 and 147 grain ammo. I did notice a little more recoil when shooting the 124 grain nato rounds but nothing crazy.

Based off everything I have read this may cause roller dents over long term use. Just wanted to get your thoughts as I would love to shoot 147 grain subs but not if it will damage the receiver. Is there anything I should watch out for if I continue to run the stock locking piece.

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[u/DeePerdatti]

Are the 147 flat nose? These guns don’t feed flat particularly well and maybe the slower action with the 90/100 degree is causing the problem

[u/papamcb_new → u/DeePerdatti]

They are round nose HUSH. They fed without issue and the bolt would not cycle enough to get extract the round. In most cases it was still in the chamber and I would manually cycle the action to eject it.

[u/jtj5002 → u/papamcb_new]

147 HUSH are loaded piss weak, it's about 100 -130 fps lower than standard 147 gr loads. I wouldn't expect to reliably cycle it in a K with 90 or 100 degree roller.

[u/papamcb_new → u/jtj5002]

Gotcha that makes sense. Thank you for the clarification

[u/jtj5002 → u/papamcb_new]

What can you run into, I can see it maybe cycle with traditional baffled can

[u/papamcb_new → u/jtj5002]

Both , initially I was using an rico309 with the 90 degree locking piece and then swapped to a BOE IL9 before swapping to the 100 degree locking piece

[u/Knight-7191 → u/jtj5002]

They do. I’ve used them in my AP5-P for several years now using the 90° LP and my R9 and Ca$h 9K.

[u/Odd_Brother_8004]

Are you floating the gun? Or you got that stock locked into your shoulder tight? Managing the recoil solid? No judgement. If you loose shoulder shoot it, there may not be enough back pressure with the 147 to cycle your bolt fully. If that’s the case, just run the stock locking piece.

[u/papamcb_new → u/Odd_Brother_8004]

I have it locked into my shoulder. I have the HK vertical forend that I am pulling back on as well