Are 40 Palmetto arms / quarter circle 10 upper

Palmetto Arms lower, Quarter Circle 10 barrel and Bolt.

Having a feed problem. It jams a round after about 3-4 shots. What it appears is on the bottom of the bolt, there is a lip that picks up the round. However it seems to big, sometimes won’t let the round enter the extractor completely and pushes it in at an angle and jams. Have pictures but evidently can’t upload them
… anyone have any experience

If you think it is the bcg you should try to shoot it with another one so you can narrow down the issue. Could be a number of things but try a buddies bcg and have him try yours.

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Agreed, try new mags also for an easy trouble shoot.

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Don’t know anyone else that has this gun and I have tried different mags, even my duty mags… it uses 40 cal Glock mags

Make sure your lower and barrel match up. An AR15 lower won’t work with a M4 barrel. I find the best setup is a M4 lower feed ramps with a M4 barrel.

I’m slightly confused on what you are saying… what do you mean m4 barrel vs ar lower?

I didn’t say it was an M4… it’s a 40 cal. (16in barrel ) on an AR PLATFORM

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Palmetto arms lower and a QC10 BCG and barrel…

I’m sorry I thought you were building something in .223 or 5.56. where lowers and barrels should be matched. I don’t have experience in .40 cal. on an AR platform. I was trying to help.

I appreciate any help… but thank you…

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Jason I’m still confused on what you are trying to say. I don’t mean to sound rude at all, but I can flip flop and lower I have with an upper that’s .223/5.56 or just .223, it’s the upper you should be considered with as far as not firing the wrong caliber out of it. I may be misreading what you are saying and I’m sorry to stray the convo from the OPs question.

Any ar15 lower, obviously not an AR10 lower receiver. I think you are thinking more of the m4 feedramps on the barrel extension that has issues if nonexistent with 5.56. Again I could be reading this wrong our possibly had a CVA.

I am talking about if you use AR15 lower and a barrel made for M4 feed ramps you may have feeding issues especially with 62 gn. green tip ammo. If you get a lower with M4 feed ramps matched with a barrel that is made for M4 feed ramps it normally feeds better.