Home CMMG CMMG vs BoreBuddy Firing Pins: FRT-15/Franklin Binary with 22lr Upper

CMMG vs BoreBuddy Firing Pins: FRT-15/Franklin Binary with 22lr Upper

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Here we test whether or not the BoreBuddy Premium firing pin makes a difference when using a Rare Breed FRT-15 trigger with a 22lr upper. Does replacing the firing pin eliminate light primer strikes or does it not make any difference at all?

Equipment used:
CMMG Banshee 300 Mk4 22lr Upper with 4.5″ barrel
Aero Precision lower with Rare Breed FRT-15 trigger

Aero Precision lower with Franklin Binary trigger
S&W 15-22 Magazines
BoreBuddy 22lr Bolt Weight (4 aluminum weights installed)
BoreBuddy AR22 Recoil Spring (4lb)
CCI Standard Velocity Ammo
BoreBuddy 22lr AR Premium Firing vs CMMG default spring

You can find the BoreBuddy products here:

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19 COMMENTS

  1. Measure the CMMG firing pin chisel point width. It should be no wider than .020" minimum width should be .015". You might also try a stronger hammer spring. Rimfire ammo requires more energy than center fire for ignition. If the stronger spring causes function issues, you can increase the radius on the bolt where it contacts the hammer.

  2. You can always take a file or Emory cloth to the firing pin to where it bottoms out. A few thousands. I wouldn't worry about the gun running away since it has a spring to retaining it back but you do have a risk of doing it so much that it pinging the chamber lip creating a problem with feeding and or extracting.

  3. Hey great video! Did you try using the (weaker) CMMG firing pin spring on the Bore Buddy firing pin? Might make the Bore Buddy firing pin strike more reliably. (or it might not.) I also had the issue of pulling to hard when I ran the Rare Breed trigger, but since I installed that Geisselle Super 42 buffer spring, it really doesn't matter how hard I pull now. I know the Super 42 spring is useless on this rimfire setup however. Keep up the good work.

  4. I'm still waiting for the return from armamentusa on that modification of the trigger pull upgrade. I got it back but they performed the wrong upgrade that I specified clearly, but the owner argued saying I was wrong so for another 40 bucks he'd make it right if I agreed and send it back, so now it's been two weeks and still waiting .once it arrives I'll try it along with the taccom firing pin. I'll post my findings then. I've got the worse luck, ha,ha…

  5. You are amazing with your info, and them amazing facts. I always look forward for your next drop of content. I love the .22lr in that configuration and to see thing normal people can have is also amazing……. thank you 🙏

  6. looking very good. Your A/B testing methodology works well. I'm curious if the "very light strikes" are just failure to reset/hammer follow. That will be hard to distinguish between.

  7. Try making a lighter trigger return spring for the frt! It has helped my setup dramatically. You won't have to pull the trigger as hard, making it easier for the hammer to reset the trigger. Promise!!

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