M&P 15 jammed with laser bore sighter in chamber

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timweidner

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I loaded a lit laser bore sighter from the magazine of my M&P 15. It chambered, but I didn't notice that the bolt stopped about 1/4-inch short of being fully forward. I sighted in my new scope to the laser dot about 100 feet out in the yard. When I tried to pull back the bolt to eject the bore sighter round, I found that the bolt was jammed.

When I engage the lever on the charging handle, it moves backward about 3/8-inch, but that is all. I tried moving the bolt with the indent in the side, but it doesn't budge. Before taking the gun to a qualified gunsmith, is there anything I should try?
 
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Bore sighter ejected!

I'm happy to report good news to my own post! I took a piece of 1" X 2" pine, pulled the charging handle back enough to be sure the lever on the charging handle was released, and lightly tapped one end of the board with a hammer while the other end rested against the side of the charging handle that doesn't have the lever. It moved a little with the first tap and popped back with the second tap.

The gun's action is moving back and forth just fine and all seems well. The brass bore sighter has the smallest burr on the front edge, but otherwise looks fine too. The burr may have been there from the start and could have even caused the jam?

So, I guess this is a cautionary tale about bore sighters. I thought I should load it from the magazine because the S&W manual that came with the gun emphatically states that all rounds must be loaded from a magazine. Since the bore sighter is essentially a 5.56 round without the bullet, I thought I should load it from the magazine as well. There are no instructions with the bore sighter. So should I have tried to feed the bore sighter into the chamber with the bolt drawn back and carefully eased the bolt back closed? I think I just answered my own question. :o
 
Jams like you experienced are usually caused by cartridges (or bore sighters) that are over SAAMI spec and will not fully chamber. Handloaded ammunition where the case has not been resized enough will jam in a similar fashion.
 
When I used my boresighter I didn't load it in the magazine, I manually placed it in the chamber and closed the bolt slowly. When done I opened the bolt and shook it out of the chamber not using the ejector. The boresighter is a rough guide anyway to be used to get you on the paper at the range, then fine tune from there.
 
I'm glad everything came out fine (pun intended), but never EVER hit/kick/hammer/pound on the charging handle when a case gets stuck in the chamber.

Instead, fully collapse the stock, grasp the rifle uprightly by the forestock with one hand, pull back on the charging handle with the other and with the rifle help vertically (and muzzle pointed in a safe direction) smartly rap the butt of the rifle on the ground or other solid surface until either the stuck case is extracted, or the extractor rips free from the rim.

If the latter happens, remove the BCG, take a solid cleaning rod and toss it down the barrel until the stuck case is knocked loose. Do not hammer on the rod. That will only make matters worse
 
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When this type of thing used to happen at the range when I was an RSO We'd do the following:
Hold the pistol vertically with the lip of the slide on a hard edged surface(usually the set up table at the lane). Grasp the grip with one hand with YOUR FINGER OFF THE TRIGGER. Push down on the grip with both hands and the slide will generally retract. Sometimes a sharp slap from the other hand was required to get the slide to retract.
Jim
 
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My question for any of you is why do you feel it is necessary to close the bolt on the bore-sighter? If you have the rifle level simply push the bore-sighter gently into the chamber and leave the bolt open. if you never jam it into the chamber it will never get stuck! There is no reason for closing the bolt, it is the outside of the bore-sighter that aligns it with the barrel, not the shoulder and head.

I guess it would help if the manufacturer would have provided instructions!
 
Alk8944 said:
My question for any of you is why do you feel it is necessary to close the bolt on the bore-sighter? If you have the rifle level simply push the bore-sighter gently into the chamber and leave the bolt open. if you never jam it into the chamber it will never get stuck! There is no reason for closing the bolt, it is the outside of the bore-sighter that aligns it with the barrel, not the shoulder and head.

I guess it would help if the manufacturer would have provided instructions!
Click to expand...

Because if you even slightly elevate the muzzle, the boresighter will slide out. That' why I insert it into the chamber by hand then slowly lower the bolt with the charging handle.....slowly. If you don't slam the bolt home all the bolt does it stop it from sliding out rearwards as the ejector never grabs. Then open the bolt slowly, raise the muzzle and the bore sighter comes right out with no chance of it jamming.

Easy peasy.
 
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