Heavy bolt lift/jam on rem700 questions

[eldest584]

Hey guys, was testing out my buddies rifle yesterday. He has a rem700 AAC sr or something, a 20" 308 rem700 with a threaded heavy contour barrel.

Testing some reloads we go from basically no pressure signs and reasonable bolt lift to a completely locked bolt. Required a solid amount of force to move the bolt up and a significant amount of force to get the bolt rearward to eject the case. Really no pressure signs on the case itself other than very slight cratering on the primer pocket with no ejector smear that I can see.

There appears to be some galling on the side of the case making me think there may be a bur inside of the chamber. I didn't notice the galling until I had gone back home and no longer had the rifle in my possession.
The fired case would not rechamber. I could place the case into the chamber with my fingers, push the bolt forward until the extractor engaged and would immediately get resistance in slide the bolt back without ever locking it down.

Is this in any way a head space issue? Unfired rounds feed very smoothly. And eject smoothly as long as they have not been fired. This is reloaded ammunition, FL resize, trimmed to 2.005", case thickness at the neck is .015", neck diameter is .335 without a bullet seated into it and .337 with a bullet seated into it. Fired case the neck OD measured to .346 I believe. I actually don't remember 100% on that measurement, but it was around .347-.344, and I can measure the OD of the fired case neck when I get home.

This is the first time I've shot my buddies rifle or tried my reloads in them. Used 43grns varget with a 178grn eldx, fired out if my rifle there were zero pressure signs at all. Nice round primer and no cratering. In his rifle, only slight cratering as seen in the picture. Unfortunately I do not have a headspace comparator yet. I have one on order from amazon so I can measure how much the shoulder moved after being fired compared to a freshly resized case.

My buddy has shot some lighter hunting factory ammo, hornady american whitetail ammo, both 150grn and 165grn factory ammo. All of those cases had cratered primers, but had never had problems with extraction or heavy bolt lift. I can't say with 100% certainty how loose the bolt lift was with those factory rounds as I was not there and my buddy is new to shooting and may have just assumed a heavy bolt lift was normal. However. When the bolt is getting jammed that obviously isnt supposed to happen.


Sorry for the long post guys but I am just looking for ideas of what it may be. I really don't think it is simply an overpressure load. I have run some stupid high overpressure loads in my rifles, to include a rem700, to the point I was popping primer pockets and have never had a bolt seized up this badly.

 

[eldest584]

Hey guys, was testing out my buddies rifle yesterday. He has a rem700 AAC sr or something, a 20" 308 rem700 with a threaded heavy contour barrel.

Testing some reloads we go from basically no pressure signs and reasonable bolt lift to a completely locked bolt. Required a solid amount of force to move the bolt up and a significant amount of force to get the bolt rearward to eject the case. Really no pressure signs on the case itself other than very slight cratering on the primer pocket with no ejector smear that I can see.

There appears to be some galling on the side of the case making me think there may be a bur inside of the chamber. I didn't notice the galling until I had gone back home and no longer had the rifle in my possession.
The fired case would not rechamber. I could place the case into the chamber with my fingers, push the bolt forward until the extractor engaged and would immediately get resistance in slide the bolt back without ever locking it down.

Is this in any way a head space issue? Unfired rounds feed very smoothly. And eject smoothly as long as they have not been fired. This is reloaded ammunition, FL resize, trimmed to 2.005", case thickness at the neck is .015", neck diameter is .335 without a bullet seated into it and .337 with a bullet seated into it. Fired case the neck OD measured to .346 I believe. I actually don't remember 100% on that measurement, but it was around .347-.344, and I can measure the OD of the fired case neck when I get home.

This is the first time I've shot my buddies rifle or tried my reloads in them. Used 43grns varget with a 178grn eldx, fired out if my rifle there were zero pressure signs at all. Nice round primer and no cratering. In his rifle, only slight cratering as seen in the picture. Unfortunately I do not have a headspace comparator yet. I have one on order from amazon so I can measure how much the shoulder moved after being fired compared to a freshly resized case.

My buddy has shot some lighter hunting factory ammo, hornady american whitetail ammo, both 150grn and 165grn factory ammo. All of those cases had cratered primers, but had never had problems with extraction or heavy bolt lift. I can't say with 100% certainty how loose the bolt lift was with those factory rounds as I was not there and my buddy is new to shooting and may have just assumed a heavy bolt lift was normal. However. When the bolt is getting jammed that obviously isnt supposed to happen.


Sorry for the long post guys but I am just looking for ideas of what it may be. I really don't think it is simply an overpressure load. I have run some stupid high overpressure loads in my rifles, to include a rem700, to the point I was popping primer pockets and have never had a bolt seized up this badly.

In one of the pics you can see a slight smear on the case head but I think that is more of a false positive for an ejector smear since there is no dent or outline of an ejector at the beginning of the smear.

 

[Supersubes]

The longitudinal scoring above the extractor groove is not right. Looks like a remington I had once that had a defective chamber from the factory. They had used some sort of holding technique during manufacture that rolled some material from the breech counterbore into the chamber. Would lock up tight with normal pressure loads, and leave marks like you have there. You could see this just by looking in the back of the action.

 

[ShtrRdy]

That primer looks pretty darn flattened.

The burrs on the side of the case look like they may have been created when you tried to put the fired case back in the chamber.

For a Headspace gauge I use a .40 S&W case and place the mouth of the case onto the shoulder of the case you want to measure. If you look at the SAAMI drawing for the .308 Win the Headspace is the point on the shoulder where the diameter is 0.400".

 

[eldest584]

That primer looks pretty darn flattened.

The burrs on the side of the case look like they may have been created when you tried to put the fired case back in the chamber.

For a Headspace gauge I use a .40 S&W case and place the mouth of the case onto the shoulder of the case you want to measure. If you look at the SAAMI drawing for the .308 Win the Headspace is the point on the shoulder where the diameter is 0.400".

I agree the primer is pretty flat too.

This is a pic of the factory ammo fired from the rifle. And afaik the hornady american white tail ammo is super under max pressure, but is still getting a sizable crater.
Obviously next step is to just load some way slower charges, but I really feel like there must be something screwy with the rifle for it to be having these issues.

 

[eldest584]

The longitudinal scoring above the extractor groove is not right. Looks like a remington I had once that had a defective chamber from the factory. They had used some sort of holding technique during manufacture that rolled some material from the breech counterbore into the chamber. Would lock up tight with normal pressure loads, and leave marks like you have there. You could see this just by looking in the back of the action.

What did you do to fix it? -Is that something that could be fixed by a gunsmith running a reamer through it by hand real fast? Or did you end up just getting rid of the rifle?

I'll have my buddy inspect his chamber or take a look at it next time I'm at his place.

 

[Supersubes]

Reamers cut like butter, so it was easy to cut by hand.

 

[eldest584]

The burrs on the side of the case look like they may have been created when you tried to put the fired case back in the chamber.

Good chance that is true, I have just never seen anything like that and wasn't sure. And I honestly don't remember if I saw them before attempting to rechamber the cartridge. I only remember trying to rechamber it about 3 times.
Here are 3 pics of 3 different spots on the case with burrs. On the last pic you can see the burrs from the second pic on the left side just a little. The first picture has a burr that parallels the case head rather than being perpendicular like the other ones.

 

[eldest584]

Someone reccomended I put a bullet into the fired case and see how snug it is. Turns out that it was fairly snug going in to the neck of the fired case out of his rifle. Compared to the fired cases out of my rifle the bullet just drops in.
Which might mean just a really dirty chamber.

 

[Supersubes]

Someone reccomended I put a bullet into the fired case and see how snug it is. Turns out that it was fairly snug going in to the neck of the fired case out of his rifle. Compared to the fired cases out of my rifle the bullet just drops in.
Which might mean just a really dirty chamber.

That could just be a dented neck as well.

 

[supercorndogs]

Where did the brass come from? The marks around it look like marks from sizing to me. Is the sizing die a little dirty or rough?

The brass looks like it was fired in something with a solid ejector. Maybe like an FAL. So I am guessing its was once fired when you got it?
Maybe a small base die is needed.

The internal capacity if the brass is going to decide how hot that load is. In Lapua it would be a no go in my 308, in Winchester brass, it would be fine.

 

[eldest584]

Where did the brass come from? The marks around it look like marks from sizing to me. Is the sizing die a little dirty or rough?

The brass looks like it was fired in something with a solid ejector. Maybe like an FAL. So I am guessing its was once fired when you got it?
Maybe a small base die is needed.

The internal capacity if the brass is going to decide how hot that load is. In Lapua it would be a no go in my 308, in Winchester brass, it would be fine.

Brass came from some cheap milsurp ammo I shot in my rem700. Die is cleaned after every reload session. As stated earlier the reloads work well and are way under max pressure in my other rifles. But in my friends rem700 they are locking the bolt. I understand that every rifle is different, but I am just surprised that even with light factory ammo we are getting solid overpressure signs which is what was making me think that there may be something else at play. Or it is just an extremely slow gun... next week we plan on backing the charges way down and seeing where we start to see the lowest pressure signs, and then see what kind of velocity he is getting. At which point it might be worth running h4350 since it is such a slow powder anyways, might get a more consistent burn that way by not having so much empty space in the case.

 

[918v]

H4350 in a 308? Wtf?

 

[eldest584]

H4350 in a 308? Wtf?

I'm running varget atm. But if my buddies rifle continues to have pressure issues at really low charges of varget I might run a slower powder so there isn't so much empty space in the case. Some people believe having a near compressed load allows for a more consistent burn. And in my personal experience I have had my lowest SD loads come from compressed loads. So who knows.

 

[ShtrRdy]

Is it possible your friends rifle barrel hasn't been cleaned in a L.O.N.G time? There could be some serious carbon build up in the throat area.

 

[eldest584]

I'm running varget atm. But if my buddies rifle continues to have pressure issues at really low charges of varget I might run a slower powder so there isn't so much empty space in the case. Some people believe having a near compressed load allows for a more consistent burn. And in my personal experience I have had my lowest SD loads come from compressed loads. So who knows.

And I'm all for experiments.

 

[Ryridesmotox]

I'd put money on a chamber cut issue. Like they didnt polish the chamber out well enough and there is a burr in there or something. You could take a good look in it and see, or a gunsmith can. May need to polish the chamber or have it recut. I have not been impressed with factory Remington stuff of late. Seems like they are not QCing things as well as they should be, and mistakes are getting through. Might be worth a call to Remington to see if theh will fix it for him.

Good luck figuring it out.

 

[918v]

I'm running varget atm. But if my buddies rifle continues to have pressure issues at really low charges of varget I might run a slower powder so there isn't so much empty space in the case. Some people believe having a near compressed load allows for a more consistent burn. And in my personal experience I have had my lowest SD loads come from compressed loads. So who knows.

H4350 will get you 2300 FPS. Why not solve the problem instead? Clean the barrel, clean the chamber, shoot some factory ammo in it, go from there.

 

[Doom]

Don’t go by primer cratering. Remington 308s will crater the primer almost all the time. They have claimed they chamfer the firing pin hole. Mine does it from starting loads to max loads.

 

[eldest584]

H4350 will get you 2300 FPS. Why not solve the problem instead? Clean the barrel, clean the chamber, shoot some factory ammo in it, go from there.

Well that is the plan. But it also not my rifle and my buddy is tight on money at the moment.

 

[mcfred]

Rem 700s of recent manufacture are notrious for having little if any primary extraction cam. Could be a contributing factor with high pressure loads. I'd look into it as part of your diagnostics.

 

[eldest584]

Rem 700s of recent manufacture are notrious for having little if any primary extraction cam. Could be a contributing factor with high pressure loads. I'd look into it as part of

Did a little research on that almost described the issue perfectly. Bolt comes all the way up, no click and extremely difficult to pull back.

Maybe this in conjunction with a touch chamber or something. Think I should have hands on my buddies rifle again tomorrow, so I might be able to check it out then.

 

[spife7980]

 

[918v]

Did a little research on that almost described the issue perfectly. Bolt comes all the way up, no click and extremely difficult to pull back.

Maybe this in conjunction with a touch chamber or something. Think I should have hands on my buddies rifle again tomorrow, so I might be able to check it out then.

308’s don’t really use the primary extraction mechanism, they extract easily on their own. Bend a paper clip and run it against the chamber wall. Maybe you’ll identify the rough area.

 

[Doom]

For what its worth, related to a dirty rifle, I have twice shot reloads with 8208xbr and Power Pro Varmint without cleaning between the powders and both times the gun has fouled and I started to see pressure signs. It didn’t take more than three rounds. I can’t say why this is happening but its real. At least those two powders don’t play well together.