My M&P 10 has about 150 rounds through it and I noticed that casings are hitting the ejection port when cycling. It's removed the anodized finish off and starting to damage the port edge. I've used federal 168 smk and Remington corelokts and it does the same for both. The casings are dented and there are also two sharp dings on the end of the casing where they appear to be hitting/scraping during ejection. This my first AR style rifle so I am still learning. Any quick fixes for this? The rifle has been reliable thus far.
Got an issue with ejection
- Thread starter Gordini47
- Start date
Register to hide this ad
rojodiablo
Member
- Joined
- Sep 17, 2011
- Messages
- 1,759
- Reaction score
- 1,190
The BCG is coming back really fast.
A question or 2; If you are looking straight forward, at what angle does the rifle eject ammo to? As in, looking down on yourself from above when shooting, you are the hands of a clock, pointed at 12. Where does the brass fall?
A pic of the brass if possible might shed a little more light on this.
A bolt which recoils really fast usually has a couple issues- yours, which is only a serious issue if you want to reload and don't want a bunch of banged up brass. Sometimes a bolt moving really fast will have an issue stripping the next round from the magazine because it comes forward so fast the magazine does not have time to feed the next round into place to be stripped into battery.
Is this rifle brand new? As in, just off the truck new, and not on the shelves for 4 months? If so, S&W might have lightened up the spring to account for the issues they have had with some M&P10 rifles not stripping ammo.
Some thoughts were the ammo being shot was not strong enough. Usually, this is a non-issue with a well set up rifle. They should cycle just about any ammo you would feed them. (The ammo you are using is just fine. I am speaking of reloads, and a variety of surplus ammo and economy ammo.)
In reality, the spring pressure, weight of the BCG, amount of gas coming back all add up to how the rifle works.
If I were to guess, and the rifle is brand new, S&W went to a slightly lighter spring to allow the bolt to absolutely retract 100% with almost any ammo. It would basically correct the issue they have been having with their rifles. On the other hand, it might dent brass and eject brass 10 feet, out around 5 o'clock, nearly behind you.
So long as it cycles ammo cleanly, you are not going to hurt it. There are buffer stops built in, so yes it might be an abrupt recoil, but if the rifle works? Then the rifle works.
A question or 2; If you are looking straight forward, at what angle does the rifle eject ammo to? As in, looking down on yourself from above when shooting, you are the hands of a clock, pointed at 12. Where does the brass fall?
A pic of the brass if possible might shed a little more light on this.
A bolt which recoils really fast usually has a couple issues- yours, which is only a serious issue if you want to reload and don't want a bunch of banged up brass. Sometimes a bolt moving really fast will have an issue stripping the next round from the magazine because it comes forward so fast the magazine does not have time to feed the next round into place to be stripped into battery.
Is this rifle brand new? As in, just off the truck new, and not on the shelves for 4 months? If so, S&W might have lightened up the spring to account for the issues they have had with some M&P10 rifles not stripping ammo.
Some thoughts were the ammo being shot was not strong enough. Usually, this is a non-issue with a well set up rifle. They should cycle just about any ammo you would feed them. (The ammo you are using is just fine. I am speaking of reloads, and a variety of surplus ammo and economy ammo.)
In reality, the spring pressure, weight of the BCG, amount of gas coming back all add up to how the rifle works.
If I were to guess, and the rifle is brand new, S&W went to a slightly lighter spring to allow the bolt to absolutely retract 100% with almost any ammo. It would basically correct the issue they have been having with their rifles. On the other hand, it might dent brass and eject brass 10 feet, out around 5 o'clock, nearly behind you.
So long as it cycles ammo cleanly, you are not going to hurt it. There are buffer stops built in, so yes it might be an abrupt recoil, but if the rifle works? Then the rifle works.
Thanks for the reply. The ammo is ejecting at about 3 or 4 o'clock with a lot of energy. I could see the brass ejecting 8 ft easy. The rifle is about 4 months old, I just haven't done much shooting.
Any idea on a quick fix/adjustment i can make to slow it down a bit?
Thanks.
Any idea on a quick fix/adjustment i can make to slow it down a bit?
Thanks.
rojodiablo
Member
- Joined
- Sep 17, 2011
- Messages
- 1,759
- Reaction score
- 1,190
My usual answer for M&P10's has been to add weight to the buffer. But your issue is a little different.
My suggestion is to pull the buffer tube spring, and cut a plastic washer to install at the back of the buffer tube, down in the hole. Try stacking them like shims. Say, 1/16" thick plastic washers from Home Depot or True Value. Get some that are a really good match, and try 2 of them at first. Then, add one, or remove one, etc. until you might see an improvement on the brass hitting the upper.
The washers will add a little preload on the spring. Too much will cause your spring to bind, so I would not go more than say 1/4-5/16" thick, give or take. Often, a longer buffer will be added to make a stop which will limit travel, but not affect the spring rate. I am just giving you the cheap and fast way to test stuff.
If it makes for problems, you take them out, and use the washers for drain pan gaskets when you change your oil. It might take a couple tries to get the rifle where you want it. Adding weight to the buffer will probably not fix this issue, as your rifle seems to cycle well enough to strip the next round dependably. (That has been the M&P issue most commonly noted. And, FWIW, it tends to be a problem when mixing and matching AR parts, in all calibers.)
Keep us posted, and if there are changes, let me know. I will try to toss more ideas your way.
BlueOvalBandit
Member
Pull the bolt back all the way with the charging handle and tell me how much of the bolt is in the port, about 1/8" of the bolt should be exposed give or take. If its too much the bolt is traveling too far back, you can put quarters in the buffer tube.
Personally I'm not seeing much of an issue beyond cosmetic. It's functioning, I'd keep shooting and when you need to make it all purty again, get some alumablack or a plain black sharpie and fancy it back up again.
Dings give firearms character
Personally I'm not seeing much of an issue beyond cosmetic. It's functioning, I'd keep shooting and when you need to make it all purty again, get some alumablack or a plain black sharpie and fancy it back up again.
Dings give firearms character
Similar threads
- Locked
