Jamming up

My AR-10 which was recently assembled and is jamming up. It is slamming the bullet and putting a very large bent in one side of the casing, almost piercing a hole in the side. I have cleaned it tried oiling it ( helped for a few rounds. Pulling it back and letting it load it is jamming the bullet in so hard that i have to smake the butt on the ground while pulling back to get it to eject

jhites said:

My AR-10 which was recently assembled and is jamming up. It is slamming the bullet and putting a very large bent in one side of the casing, almost piercing a hole in the side. I have cleaned it tried oiling it ( helped for a few rounds. Pulling it back and letting it load it is jamming the bullet in so hard that i have to smake the butt on the ground while pulling back to get it to eject

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Wondering what is wrong???

Tried a different mag?

Bob Wright said:

Tried a different mag?

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factory ammo or reloads?

Try adjusting the magazine feed lips so the bullet presents nose up rather than nose diving

I would look at the feed ramps and also maybe a lighter buffer spring. Or a heavier buffer weight. The dent is it in the front or rear of case? when you say it's jamming the bullet in do you mean the cartridge is jammed in the chamber or the bullet is jamming into the lands of the barrel?
To me it seems that the cartridge is coming out of the magazine at the wrong angle and causing a dent when hitting the front of chamber.
This could be the feed ramps are not cut correctly or the barrel was not installed correctly. Just a guess.

Also it could be the bolt is not picking up the cartridge correctly.

OP has a duplicate post, https://www.longrangehunting.com/threads/jamming-up.365022/#post-3159231

what brand of lower receiver is this? is it an 80%? sometimes those are not precisely in-spec, the mag catch location. perhaps the mag is not sitting up high enough for the bolt to pick up back face of the cartridge from the mag?

Bob Wright said:

Tried a different mag?

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Yes

Rotten said:

I would look at the feed ramps and also maybe a lighter buffer spring. Or a heavier buffer weight. The dent is it in the front or rear of case? when you say it's jamming the bullet in do you mean the cartridge is jammed in the chamber or the bullet is jamming into the lands of the barrel?
To me it seems that the cartridge is coming out of the magazine at the wrong angle and causing a dent when hitting the front of chamber.
This could be the feed ramps are not cut correctly or the barrel was not installed correctly. Just a guess.

Click to expand...

They have usually been jamming up in the chamber like standing straight up almost but trying by pulling back the charging handle, they have been getting stuck in loaded, they would probably fire but i can not pull back the charging handle without force( banging the butt down while pulling). Every time i load it they stick

Are you sure what you have is a 308 upper? You've got some serious issues going on for it to do that much damage to the cartridge. Find a good gunsmith that's a AR expert. Good luck

With out actually seeing what it's doing it's hard to give advice on a problem. But it looks like the bolt is not coming all the way back and picking up the cartridge correctly. Does this happen by slowly releasing the bolt with only 1 round in magazine? I wouldn't be shooting this gun repeatedly
until the problem is resolved. If it chambers the first round correctly I'd start looking at the grass block and making sure it's getting the correct amount of gas to move the bolt all the way to the rear. Does the bolt lock open if you load a single round and shoot it? If not the bolt is definitely not coming back all the way to strip the next round up into the bolt face.