Shoulder Bump and the Ruger American 308

[Bidwell]

I was trying the shoulder technique of removing the firing pin so I can easily detect when my brass fits just right in the chamber after bumping around .002. I'm using a Redding Premium die and the competition shell holders. I went through the whole process with the fancy shell holders but the bolt always had resistance when closing. So I just took a normal shell holder, set up the press so it touched the shell holder and a touch more so it cammed over. Using a head space comparator, the bump was now at a large .008 bump but still the bolt has resistance when closing. What am I missing? The cartidge length is below trim length so its not that. Any ideas?

 

[Shooter Mike]

Does the bolt still have the ejector pin installed?


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[Bidwell]

Does the bolt still have the ejector pin installed?


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Damn... Yeah that's it. Thanks! On all the tutorials I've watched no one has ever mentioned that. I also have no idea how to remove it. The process of taking out the firing pin was stressful too, I decompressed the spring at one point. Nightmare, but I got it assembled again. Do you think this process is worth the hassle, or just bump it back .002 and call it good?

 

[Shooter Mike]

I don’t think it’s worth the hassle. But what do I know. I bump 002” and call it good. I think the extra step of taking the bolt apart is simply for verification, but it’s somewhat subjective and depends on the friction you have in your action.


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[WeiserBucks]

Bump .002-.003 and roll with it.

 

[Bidwell]

I don’t think it’s worth the hassle. But what do I know. I bump 002” and call it good. I think the extra step of taking the bolt apart is simply for verification, but it’s somewhat subjective and depends on the friction you have in your action.


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Sold! Thanks for the input.

 

[Fireflyfishing]

Bump .002-.003 and roll with it.

This. Don’t over think it.

 

[Vern400]

I don't take the ejector pin out.
I just close the bolt empty a few times and get a feel for it. 0.001 of interference will cause difficulty closing the bolt. In my rifle 0.002 of interference the bolt won't close.
I've got my shoulder to case head dimensions written down with zero clearance. I usually just work to that number as the upper limit.

I have 0.001 to 0.003 of variation in a normal batch of cartridges that I've just resized. So when I adjust my die I'll usually resize three to five and check them all. Don't keep using the same piece of brass because that can make your results get kind of weird.

The only reason for bumping the shoulder back 0.002 just to make sure all your your case is fit in the chamber, without being stupid sloppy. If they fit without excessive bolt force, you're fine.

If you have no idea what rifle your ammunition is going to be used in, you've got to push back to the saami spec. I don't let anybody use my hand loads unless they're in my rifle anyway.

 

[gman82001]

Seeing a buddy wrestle his boys brand new American bolt getting it sighted in this weekend don’t know how’d you’d know if it was tight closing or not. Ya it shot great but good lord that was the worst bolt closing I’ve ever seen on a rifle

 

[Bidwell]

I don't take the ejector pin out.
I just close the bolt empty a few times and get a feel for it. 0.001 of interference will cause difficulty closing the bolt. In my rifle 0.002 of interference the bolt won't close.
I've got my shoulder to case head dimensions written down with zero clearance. I usually just work to that number as the upper limit.

I have 0.001 to 0.003 of variation in a normal batch of cartridges that I've just resized. So when I adjust my die I'll usually resize three to five and check them all. Don't keep using the same piece of brass because that can make your results get kind of weird.

The only reason for bumping the shoulder back 0.002 just to make sure all your your case is fit in the chamber, without being stupid sloppy. If they fit without excessive bolt force, you're fine.

If you have no idea what rifle your ammunition is going to be used in, you've got to push back to the saami spec. I don't let anybody use my hand loads unless they're in my rifle anyway.

Good advice, thanks for that.

 

[Bidwell]

Seeing a buddy wrestle his boys brand new American bolt getting it sighted in this weekend don’t know how’d you’d know if it was tight closing or not. Ya it shot great but good lord that was the worst bolt closing I’ve ever seen on

Mines not too bad, I can do it with a finger but it's definitely not smooth

 

[Vern400]

Seeing a buddy wrestle his boys brand new American bolt getting it sighted in this weekend don’t know how’d you’d know if it was tight closing or not. Ya it shot great but good lord that was the worst bolt closing I’ve ever seen on a rifle

If he's using handloads that were fired in another rifle, he's learning what I learned. But ...

If the bolt is hard or sticky sliding or closing the factory isn't doing a great job. I just developed loads for a brand new Howa and the bolt was sticky sliding rearward. It would close and open okay but it would get stuck and wouldn't slide back even with the bolt raised.

Anyhoo, if a new bolt gun closes or opens hard or gritty, a little bit of lapping compound and working that bolt a couple hundred times does wonders if it's just a surface finish problem. One TV episode working the bolt should smooth it up if there's nothing fundamentally wrong.

Clean it up thoroughly though. Lapping compound can have unintended consequences if it gets in the wrong place. Right or wrong, I use the same stuff that I lap automotive intake and exhaust valves with.

 

[jjohnsonElknewbie]

I watched a video the other day of probably the easiest and most repeatable way to set up your FL sizing die for bump. Get a feeler gauge from amazon or auto parts store. They typically run around $10 bucks and include a .0015 and .0025 gauge.

1. EDIT: remove the decapping rod from the FL die
2. Extend the ram completely like normal and screw your FL die down almost all the way to the shell holder (standard SAAMI FL size).
3. Insert whatever gauge you want based on your preferred bump in between the standard shell holder and the die.
4. Resume screwing down the die until it sandwiches the gauge against the shell holder. Tighten your lock ring from there, and you should be able to slide the gauge in and out of the gap.
5. EDIT: reinstall the decapping rod
6. Size a fired piece of brass and compare to an unsized and fired piece of brass. You should have the same bump for all of your brass +/- variation in the brass.

This eliminates any guesswork, multiple measurements, and trial/error.

 

[gman82001]

If he's using handloads that were fired in another rifle, he's learning what I learned. But ...

If the bolt is hard or sticky sliding or closing the factory isn't doing a great job. I just developed loads for a brand new Howa and the bolt was sticky sliding rearward. It would close and open okay but it would get stuck and wouldn't slide back even with the bolt raised.

Anyhoo, if a new bolt gun closes or opens hard or gritty, a little bit of lapping compound and working that bolt a couple hundred times does wonders if it's just a surface finish problem. One TV episode working the bolt should smooth it up if there's nothing fundamentally wrong.

Clean it up thoroughly though. Lapping compound can have unintended consequences if it gets in the wrong place. Right or wrong, I use the same stuff that I lap automotive intake and exhaust valves with.

Oh it’s absolutely the way it is from the factory it was just brand new precision hunter ammo but the bolt was horrible trying to chamber a round. I told him to chamber a few of the fired brass a bunch of times to see if it’ll smooth it up any but he’s not really a gun guy so recommending anything more than that will probably overwhelm him lol

 

[Fireflyfishing]

I watched a video the other day of probably the easiest and most repeatable way to set up your FL sizing die for bump. Get a feeler gauge from amazon or auto parts store. They typically run around $10 bucks and include a .0015 and .0025 gauge.

1. Extend the ram completely like normal and screw your FL die down almost all the way to the shell holder (standard SAAMI FL size).
2. Insert whatever gauge you want based on your preferred bump in between the standard shell holder and the die.
3. Resume screwing down the die until it sandwiches the gauge against the shell holder. Tighten your lock ring from there, and you should be able to slide the gauge in and out of the gap.
4. Size a fired piece of brass and compare to an unsized and fired piece of brass. You should have the same bump for all of your brass +/- variation in the brass.

This eliminates any guesswork, multiple measurements, and trial/error.

Interesting. I’ll give this a shot. Thanks.

 

[Vern400]

Oh it’s absolutely the way it is from the factory it was just brand new precision hunter ammo but the bolt was horrible trying to chamber a round. I told him to chamber a few of the fired brass a bunch of times to see if it’ll smooth it up any but he’s not really a gun guy so recommending anything more than that will probably overwhelm him lol

The Howa rifle in 308 I loaded for had a fairly tight chamber, at the low end of the Saami specs.
I had to set my RCBS dies up to cam -over to push shoulders back far enough to close the bolt. None of my hand loads for other rifles would fit. And there were a few pieces of factory new 150 grain FMJ that closed on tight bolt. One or two of them were very difficult to extract. I had a bucket full of LC 7.62 brass commercially cleaned and resized that wouldn't fit at all. Even when I crunched it all the way in the resizing die it was proportionally more difficult than the commercial brass. That's because it has thicker case walls and it's hard to shove back to a minimum material condition.

If you send it back they're going to check it with a go gauge and a no-go gauge and tell you it's good.

Best thing is probably to put a tight cartridge in it, oil it good and just put 500 cycles on the bolt. Lapping compound if you have to.

Shouldn't have to do that with a new rifle but it is what it is.

 

[rgrx1276]

I use an RCBS Precision Mic PN 88329... Solves a lot of dicking around with trying to figure out how much to set a shoulder back