RandyBaker Posted May 30, 2020 Share Posted May 30, 2020 I have a JP GMR15 lower and short stroke BCG. Will any 9mm upper work this? I searched and couldn’t find the answer. Thanks Link to comment
Darqusoull13 Posted May 30, 2020 Share Posted May 30, 2020 For the most part if it's a standard AR pattern yes. Bolts will need central weights removed if solid / non-JP. Best advice is to just get a JP upper though. Link to comment
RandyBaker Posted May 30, 2020 Author Share Posted May 30, 2020 16 minutes ago, Darqusoull13 said: For the most part if it's a standard AR pattern yes. Bolts will need central weights removed if solid / non-JP. Best advice is to just get a JP upper though. Thanks for the reply. The only reason for not wanting a JP upper is I was wanting just a cheaper 9mm upper to play with. since I have the JP BCG that will still work in other uppers...is that correct? thanks again Link to comment
Silverscooby27 Posted May 30, 2020 Share Posted May 30, 2020 I have a Foxtrot Mike upper that I use from time to time with a GMR-15 lower and it works great. Link to comment
CharlieD Posted May 30, 2020 Share Posted May 30, 2020 If the barrel has an extended feed ramp it may not fit due to the LRBHO on the JP. Link to comment
Darqusoull13 Posted May 31, 2020 Share Posted May 31, 2020 7 hours ago, RandyBaker said: Thanks for the reply. The only reason for not wanting a JP upper is I was wanting just a cheaper 9mm upper to play with. since I have the JP BCG that will still work in other uppers...is that correct? thanks again Correct as long as they are "mil spec" AR15 pattern. I built a bunch of uppers with JP guts off standard AR uppers. Link to comment
RandyBaker Posted June 1, 2020 Author Share Posted June 1, 2020 Thank you all for the responses Link to comment
kellymc Posted June 9, 2020 Share Posted June 9, 2020 (edited) I tried a taccom upper on a GMR 13 and the mag sat to high for the taccom bolt. Edited June 9, 2020 by kellymc Link to comment
Sniperboy Posted June 12, 2020 Share Posted June 12, 2020 On 6/9/2020 at 4:14 AM, kellymc said: I tried a taccom upper on a GMR 13 and the mag sat to high for the taccom bolt. I have had this experience too with my GMR13. I can't comment on other brands of bolts, but unless you can try ahead of time it may be safer to buy a JP bolt if you have a JP lower. Link to comment
kellymc Posted June 13, 2020 Share Posted June 13, 2020 I went ahead and built a QC lower for my taccom 5/16 upper. Seems to work fine and I leaving my GMR 13 intact Link to comment
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