M305 bolt problem

Easy 9mm

Easy 9mm

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Southeast of Wpg
-removed- bolt problem

I am having a problem with my -removed- and was hoping some of the more experienced people could offer some insight. I'm new to the -removed- platform and I tried a search on this problem and came up with nothing (maybe I'm not using the correct terminology).

The problem I'm having is that the rear of the bolt is dropping out of the track under recoil. I bought the rifle barely used (only 10 rounds through it at the time of purchase) and have put about 80 rounds of commercial Remington and federal, and about 20 handloads, through the rifle without a problem. This weekend I was at my first carbine match with the rifle (using commercial Remington ammo) to have a little fun and was making the rifle work considerably harder. After the first shot on the second stage the bolt came back but would not return to battery. I dropped the mag and tried racking it and it would not move. So I took it to the bench to disassemble the rifle and had a few guys have a look. It looked like the rear of the bolt dropped enough to leave the track and wedged itself just on the edge of the track it rides in. We tried giving it a push to get the bolt back in without any luck so I gave it a solid tap with the handle of a screwdriver and the rear of the bolt popped back into the track and the bolt closed no problem. I gave it a quick safety check and all was good again. I was able to go back and do the second stage without further problems, but it happened again in the third stage. I figured I could fix it again, finish the stage and retire the rifle until it got fixed permanently, but no dice. After the third time, I decided that was enough for the day.

Here is a picture of what it is doing. (the bolt was wedged further back during the actual failure though)
-removed-

What could cause this to happen and what would be the solution?:confused:
 
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Is it also binding on the receiver on the right lug where the lug and roller pass under the rear sight/charger bridge?

And she looks kinda dry, have you greased her?
 
45ACPKING said:
Is it also binding on the receiver on the right lug where the lug and roller pass under the rear sight/charger bridge?

And she looks kinda dry, have you greased her?
Click to expand...

The bolt is quite loose at all the other points with no binding or wear that I can see. I'm not sure if it could be too loose which could cause the rear of the bolt to drop out like that and then bind when it gets hammered back by recoil.

The first thing I did when I took it home after the failures, I cleaned up all the grease to check what was allowing the bolt to drop and if there was any wear or damage, so the photo shows it before it has been re-greased and put back together. This has got me thinking though that my grease could be a part of the problem. It was quite hot out that day and the cheap CT grease was looking real thin when I went to clean it up.

Sluggo_m14 said:
Were the Rem bullets 180gr by chance?
Click to expand...

These were Rem 150 grain Pointed soft points.

Thanks for the replies so far.
 
LordEvilPepper said:
why is there a J hook in the rear lug on the bolt? is it missing a chunk?

If not... either your bolt or reciever is out of spec (or both), there is no way for it to do that otherwise.
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I'm not completely clear what you are referring to. I took a few more pictures of the bolt. Is there any way to find out what the specs are for the bolt and receiver to verify if they are within tolerance?

cya0.jpg


ou3o.jpg


7opn.jpg


2drt.jpg


5xcd.jpg
 
I'm not sure what the actual dimensions of spec are..... got a set of calipers?

measure across the rails, then across the widest point on the rear bolt lugs.

I'm sure we can compare those to others (like mine, 45acp's and other persons) and get an idea how much of a difference there is.

the "hook" im talking about is that diviot at the base of the rear lug.... mine does not have that its a completely flat back, no bevel at the bottom

....I will grab dimensions tonight... battery in my caliper is dead....
 
LordEvilPepper said:
I'm not sure what the actual dimensions of spec are..... got a set of calipers?

measure across the rails, then across the widest point on the rear bolt lugs.

I'm sure we can compare those to others (like mine, 45acp's and other persons) and get an idea how much of a difference there is.

the "hook" im talking about is that diviot at the base of the rear lug.... mine does not have that its a completely flat back, no bevel at the bottom

....I will grab dimensions tonight... battery in my caliper is dead....
Click to expand...

I also forgot to mention this is a 2012 marked -removed-, if it is worth anything.

I grabbed the calipers and measured a few points.

#1 - 1.145"
#2 - 1.082"
#3 - 0.978"
#4 - 0.985"
#5 - 1.113"

I take it the hook you are talking about is #6 in the picture; the bolt was machined like that with no bare steel visible there.

qq1p.jpg
4p2s.jpg
 
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Easy 9mm said:
I'm not completely clear what you are referring to. I took a few more pictures of the bolt. Is there any way to find out what the specs are for the bolt and receiver to verify if they are within tolerance?

cya0.jpg


ou3o.jpg


7opn.jpg


2drt.jpg


5xcd.jpg
Click to expand...

Hi :)
I thought there was something weird about your lug so I stripped mine down so you can see for yourself.
Mine is 90 degrees to the body if you know what I mean (I aint no weapon tech).
Yours looks badly worn mate :(


At least you have an idea what it should look like
Cheers and good luck :)


Posted before I saw yours was a 2012 :(((( Definitely not getting one of the new ones. Mines a 2009.so you can see the difference in quality its hardly worn at all.
 
Lost...again said:
Hi :)
I thought there was something weird about your lug so I stripped mine down so you can see for yourself.
Mine is 90 degrees to the body if you know what I mean (I aint no weapon tech).
Yours looks badly worn mate :(


At least you have an idea what it should look like
Cheers and good luck :)


Posted before I saw yours was a 2012 :(((( Definitely not getting one of the new ones. Mines a 2009.so you can see the difference in quality its hardly worn at all.
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I grabbed a few more pics of the bolt. From the top, it looks like yours, but from the the end, I can see where they machined a little too far in to the lug. I have a feeling that it is unrelated to my original problem, but could be a good indication that the bolt may be out of spec.

Also, is this much wear normal after 200 rounds? Or is it just a matter of rough machining rubbing against rough machining?

0akv.jpg
tks3.jpg
 
An opinion is like an #######, but seeing as how you asked LOL
It seems that there have been more issues with the newer imports regarding QC. My rifle has been thru around 2000 rds (that I know of, and probably a lot more) and the bolt looks a lot newer than yours.
But like I said...its an opinion and I could be full of sh-t :)
Stay tuned because this is going to take off later when everybody gets in.
Good luck again mate :)
 
I almost agree with you, but considering it is a used rifle we do not know if the previous owner just shot the crap out of it and then sold it.

Some people still don't know your supposed to grease them(not referring to the op)

Once I get more milage on my 2012 I will let you know.
 
Wow thats a lot of wear and tear.

I thought this was a newish rifle. The future shop I stopped at was out of batteries that fit my calipers, so I will try another store tommorow. but If its just a worn bolt, I can send you mine I got a new one coming, I was just going to chuck the old one.
 
LordEvilPepper said:
Wow thats a lot of wear and tear.

I thought this was a newish rifle. The future shop I stopped at was out of batteries that fit my calipers, so I will try another store tommorow. but If its just a worn bolt, I can send you mine I got a new one coming, I was just going to chuck the old one.
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Wow, thanks for the offer (isn't this community great?), but before I would take you up on it I would like to try a few things. Who knows, it may be the receiver that's out of spec and the problem would just resurface with a different bolt. If it does end up being the bolt, I would be more than happy to send you a couple bucks to cover shipping for the bolt.

I wonder if the excessive wear on the bolt is a result of a softer bolt against rough machining in the receiver, which is real rough, or did I screw something up when greasing it? Maybe I forgot to hit that spot in the receiver the first time out (I was real excited when I first got it and went through the inspection and re-greasing pretty quickly so I could take it to the range.)
 
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