Saum won’t chamber after shooting session

[Highvoltage]

I'm shooting 6.5 saum with adg brass and h1000. I've verified pressure through testing and now I'm doing a load work up. The rifle has roughly 150 rounds through it. I've noticed after shooting a string of 5-6 shots it gets harder and harder to close the bolt. As I was working toward finishing my ladder I just quit shooting due to the pressure it took to close the bolt. Everything was sized at the same time during prep. So I don't think the issue is the reloading itself. Could my chamber need cleaned or is it the heat from the string? I've never cleaned the chamber yet. If a chamber cleaning would solve this issue what's everyone's preferred method? Best wishes.

 

[FEENIX]

I'm shooting 6.5 saum with adg brass and h1000. I've verified pressure through testing and now I'm doing a load work up. The rifle has roughly 150 rounds through it. I've noticed after shooting a string of 5-6 shots it gets harder and harder to close the bolt. As I was working toward finishing my ladder I just quit shooting due to the pressure it took to close the bolt. Everything was sized at the same time during prep. So I don't think the issue is the reloading itself. Could my chamber need cleaned or is it the heat from the string? I've never cleaned the chamber yet. If a chamber cleaning would solve this issue what's everyone's preferred method? Best wishes.

Provide as much pertinent information as possible, i.e., load charge/velocity, primer pix, brass measurements (~.002" shoulder bump)/condition (trim), etc.

 

[Gamesniper19]

I'm shooting 6.5 saum with adg brass and h1000. I've verified pressure through testing and now I'm doing a load work up. The rifle has roughly 150 rounds through it. I've noticed after shooting a string of 5-6 shots it gets harder and harder to close the bolt. As I was working toward finishing my ladder I just quit shooting due to the pressure it took to close the bolt. Everything was sized at the same time during prep. So I don't think the issue is the reloading itself. Could my chamber need cleaned or is it the heat from the string? I've never cleaned the chamber yet. If a chamber cleaning would solve this issue what's everyone's preferred method? Best wishes.

Need more information but a few items to think about. I shoot the 6.5 GAP which is basically the same cartridge and depending on where you had it built, it could be a few things.

Could have a super tight chamber - SAAMI minus
Does the rifle do the same thing after you let it cool down and then fire a string again?
Where in your ladder are you loading? If you are near the top of your ladder?
What load are you shooting?

It sounds like a chamber issue. All metals expand when heated so if you have a tight chamber, that could be the culprit. Cleaning it thoroughly may solve it and it is a great place to start.

 

[Rick Richard]

It could be a good cleaning is needed if you have not cleaned in that 150 total shots fired, And, are you sure you are bumping the shoulders back far enough…checking with a tool and caliper and just not by feel?

 

[Tiny Tim]

Do you have a borescope or able to borrow one? Could be carbon buildup at the end of your case in the chamber. Is your trim length consisten?

Heat makes metal expand, so tight neck clearance should increase as diameter grows with heat.

If the ammo goes in after completely cooled at home, then you know it's temp related.

 

[cohunt]

Need more information but a few items to think about. I shoot the 6.5 GAP which is basically the same cartridge and depending on where you had it built, it could be a few things.

Could have a super tight chamber - SAAMI minus
Does the rifle do the same thing after you let it cool down and then fire a string again?
Where in your ladder are you loading? If you are near the top of your ladder?
What load are you shooting?

It sounds like a chamber issue. All metals expand when heated so if you have a tight chamber, that could be the culprit. Cleaning it thoroughly may solve it and it is a great place to start.

Holes get bigger when they are hot -- my science teacher taught us that in high school-- she said "a hole in metal is just like a woman"

 

[Highvoltage]

I just tried a loaded round 60.8 gr h1000 with a 140 ab. It won't close. I can shoot up to 61.5 without pressure, I was on 60.6gr last night. It incrementally got harder to close last evening with the ladder. I think I'm going to try and scrub it good and see how that goes. As far as the shoulder bump, I don't have gauges. (Need to invest). Trim length is consistent. Preferred barrel chambered it, it's a tikka 6.5 gap btw.

 

[Tiny Tim]

Try some good carbon remover and a bronze brush in the chamber neck area.

Again, a bore scope is a inexpensive tool that can help so long as you don't freak out by what you see. Lol

 

[Tiny Tim]

I just tried a loaded round 60.8 gr h1000 with a 140 ab. It won't close. I can shoot up to 61.5 without pressure, I was on 60.6gr last night. It incrementally got harder to close last evening with the ladder. I think I'm going to try and scrub it good and see how that goes. As far as the shoulder bump, I don't have gauges. (Need to invest). Trim length is consistent. Preferred barrel chambered it, it's a tikka 6.5 gap btw.

Did you ever make certain your resized cases would chamber. If you have a bullet puller, you could try one.

Also verify your CBTO/ OAL. We've all made measuring mistakes.

 

[Gamesniper19]

Holes get bigger when they are hot -- my science teacher taught us that in high school-- she said "a hole in metal is just like a woman"

All metal expands, so the body, neck, shoulder, lead, and bore area which means if the neck and shoulder are expanding slightly and pushing back on the cartridge, it is possible to push back hard enough in a SAAMI minus chamber to create pressure on the bolt.

I just tried a loaded round 60.8 gr h1000 with a 140 ab. It won't close. I can shoot up to 61.5 without pressure, I was on 60.6gr last night. It incrementally got harder to close last evening with the ladder. I think I'm going to try and scrub it good and see how that goes. As far as the shoulder bump, I don't have gauges. (Need to invest). Trim length is consistent. Preferred barrel chambered it, it's a tikka 6.5 gap btw.

It sounds more like a dirty chamber but if a thorough and complete cleaning does not clear up the issue, time to look at other issues.

 

[nksmfamjp]

Everything was sized at the same time during prep.

What was your CBTD target and how do your remaining unfired and fired cases compare?

Could my chamber need cleaned

Yes, sometimes chambers develop fouling in the neck, IME. That may need carbon cleaner and a brush.

 

[MagnumManiac]

I have a feeling you may have developed a carbon ring in the throat, give it a good soak with CLR and keep an eye on it in future…
If this is not the cause, another thing to look at is a gummed up bolt internally, it may be full of carbon too if the loads you are using are dirty. I would disassemble my bolts after a weekend match, clean them with Shellite and re-grease them for the next match. This is often overlooked by many as a stiff internal bolt will cause issues.
Do you use a lube on your lugs? If you are using tight chambering brass, this could also be shaving brass off the cases, making bolt rotation stiff…

Cheers.

 

[FEENIX]

Provide as much pertinent information as possible, i.e., load charge/velocity, primer pix, brass measurements (~.002" shoulder bump)/condition (trim), etc.

As far as the shoulder bump, I don't have gauges. (Need to invest).

Yes, they are one of many excellent investments in reloading. Below are my brass load measurement for fire-forming off the chamber after hydraulic forming on my .338 Thor. This one got away from me, and as you can see with the measurement, it will not chamber for obvious reasons.

 

[Mikecr]

Holes get bigger when they are hot

I don't think this is a temperature problem, but it's not always true that holes get bigger with higher temps.
It's tied to the stresses residing within the metal.
Button/broach bores get bigger, while hammer forged gets smaller. Cut rifled stays about the same.