Shoulder Bump Tolerance

[Alex Wheeler]

The press certainly plays a role here. At one time I owned 4 or 5 presses. I tested them all for shoulder bump on a dasher. The best was my Hood press. It gave more consistent bumps than any of my others including my coax. But under .001 without annealing is not unreasonable.

 

[OmegaRed]

do you anneal?

I forgot I do cam over and have a 4 second dwell,well just count to 4 lol...

Also this is with a redding body die,no particular reason for the body die but it was all I could find when looking for dies.... body die, type s bushing die, and then le wilson arbor seater. I have threatend to get a full length bushing die but its working for now, just an extra step....

Concerning the the comparotor its just the hornady out fit and it stays on a dedicated pair of calibers, and yes if you change the insert in and out it will measure different from the last time.....I did get one of the caliper jaw bases from a member here cant recall his handle), and it does help getting a consistent reading......

No I never have. 30BR brass has a good number of firings them too.

I found Redding comp shell holders to be an easy way to consistently achieve where you want to be at. I don't believe they do anything for consistency though. As other people have mentioned, I'd start with how you apply and what you use for lube. It does have an affect when you are trying to measure this small.

 

[gunsandgunsmithing]

The press certainly plays a role here. At one time I owned 4 or 5 presses. I tested them all for shoulder bump on a dasher. The best was my Hood press. It gave more consistent bumps than any of my others including my coax. But under .001 without annealing is not unreasonable.

I agree that it can be done, but why, if testing doesn't support a benefit on target and mine has yet to. Again, we're not talking bad tolerances, just maybe not the .0005 that some seek. We're very literally splitting a hair multiple times here for something that I can't see on target, nor in brass life. I tend to do what I can see helps and I've never found anything more helpful than reading the wind, once you get to a certain point, of course. Again, no harm in doing things as close to perfect as possible but that's only if your time isn't better spent shooting and learning in conditions.

 

[JMayo]

My experience is 30br doesn't care ...
.1, 2,3 4,5 thou and you won't see any difference.
The thing is bolt operation. Smooth and easy. No need to over work the brass.
I was bumping 5 or more thou for a while and shot 20+ times. Still going fine.
I just didn't do the math, just made them the same, took what the die gave me close to what i wanted i thought. I could go get my notes but Naa .. Don't want to. Jam the bullets and go.
Ps. I did kinda good in vfs last year

 

[gunsandgunsmithing]

My experience is 30br doesn't care ...
.1, 2,3 4,5 thou and you won't see any difference.
The thing is bolt operation. Smooth and easy. No need to over work the brass.
I was bumping 5 or more thou for a while and shot 20+ times. Still going fine.
I just didn't do the math, just made them the same, took what the die gave me close to what i wanted i thought. I could go get my notes but Naa .. Don't want to. Jam the bullets and go.
Ps. I did kinda good in vfs last year

You sure did, Johnny! Congrats buddy!

 

[INTJ]

Just my 2 cents worth and if you're maintaining .0005 consistency then it probably doesn't pertain to you. But, I find that a small amount of variability is normal, as in about .001. For that reason, I tend to bump my shoulders a tad more than some others do. My logic is simply that I'd rather have all cases to have easy bolt closure as opposed to some being tight and some loose. I find that scenario to be very common when we try to achieve .0005ish shoulder bump. Now, I won't take this to extremes but I don't consider .002-.003 to be excessive shoulder bump, yet enough to ensure a consistent bolt closure, ignition and harmonics. Nothing at all wrong with being a little closer to "perfect" but I don't find it to matter as much as tight vs loose.
My brass life has never come down to this. It's always been primer pockets that go first for me.
Again, just my 2 cents.

I also use .002 to .003". Nothing will mess up a 1000 yd group like sticky cycling.

 

[Bill Norris]

Bottom line for me is simply "If I can't see it on my target forget about it"

 

[gunsandgunsmithing]

I also use .002 to .003". Nothing will mess up a 1000 yd group like sticky cycling.

I haven't tested enough to narrow it down to tight cycling or other causes, but most all of us have seen a tight round go both into and out of a group. One logical way to do away with a tight round is to bump the shoulder a tad more.

 

[gunsandgunsmithing]

Bottom line for me is simply "If I can't see it on my target forget about it"

I agree 100%
This is a game where we should over think every detail, right up to the point where we find that it does or does not matter. Beyond that, seems a waste of time that is better spent pulling the trigger.

 

[Alex Wheeler]

I agree that it can be done, but why, if testing doesn't support a benefit on target and mine has yet to. Again, we're not talking bad tolerances, just maybe not the .0005 that some seek. We're very literally splitting a hair multiple times here for something that I can't see on target, nor in brass life. I tend to do what I can see helps and I've never found anything more helpful than reading the wind, once you get to a certain point, of course. Again, no harm in doing things as close to perfect as possible but that's only if your time isn't better spent shooting and learning in conditions.

Well, you are correct if the combo does not care. Some barrels are more forgiving than others. An example I use is @tom had a barrel that would shoot at .006 in, not .005 or .007 but .006. It was not a forgiving barrel at all. But with his level of loading he broke a group agg record with it which still stands. So it matters when it matters I guess is my answer.
Im not saying that this is the case, but something like a 30br is the last thing in the world a guy would want to use to test what matters and what doesnt. Very forgiving rounds, and just that. Very forgiving.

 

[gunsandgunsmithing]

The further I shoot the more I see.

Lol! Ok, but how many times has a half thou of shoulder bump cost you a match, vs pulling the trigger at the wrong time? Point being, it's still a game of whoever screws up least, wins most. At all yardages.

 

[gunsandgunsmithing]

Well, you are correct if the combo does not care. Some barrels are more forgiving than others. An example I use is @tom had a barrel that would shoot at .006 in, not .005 or .007 but .006. It was not a forgiving barrel at all. But with his level of loading he broke a group agg record with it which still stands. So it matters when it matters I guess is my answer.
Im not saying that this is the case, but something like a 30br is the last thing in the world a guy would want to use to test what matters and what doesnt. Very forgiving rounds, and just that. Very forgiving.

I've got some 30 cal 115 Bergers I'll sell ya. That seems to be the subject here. I'd come nearer to beliving the bullet is what makes it forgiving to seating depth than the cartridge, but I may be wrong. But seriously, I'd question any tune or bullet that is that sensitive.

I've seen the same anomaly with tuners...where a setting shoots phenomenally and goes to hell with one mark of tuner movement. Tested this in vibration analysis. It showed to be that bullet exit was occuring at a spike along the sine wave rather than at the top of the natural frequency anti-node.

IOW, it's possible to land on a very narrow spot that shoots great but does not give the expected results with tuner movement that does occur when it's in tune. Yes, it can happen.

 

[Alex Wheeler]

I've got some 30 cal 115 Bergers I'll sell ya. That seems to be the subject here. I'd come nearer to beliving the bullet is what makes it forgiving to seating depth than the cartridge, but I may be wrong.

No doubt some bullets are more forgiving. Most of the bullets that seem to win at 1k are a little picky. A few thou is the window. A really good barrel will shoot a powder charge all year round though. But those really forgiving bullets just have not found their way into the winners circle at 1k.

 

[Kracken McGraw]

The further I shoot the more I see.

The higher they jump, the sweeter the Breeze!

 

[gunsandgunsmithing]

No doubt some bullets are more forgiving. Most of the bullets that seem to win at 1k are a little picky. A few thou is the window. A really good barrel will shoot a powder charge all year round though. But those really forgiving bullets just have not found their way into the winners circle at 1k.

Hmmm. That's counter to the actual physics involved and perhaps the results are supporting it.

 

[Bill Norris]

Im not saying that this is the case, but something like a 30br is the last thing in the world a guy would want to use to test what matters and what doesnt. Very forgiving rounds, and just that. Very forgiving.

I was testing with a 30BR @ 100 yds. That's the only distance I have to shoot.

 

[gunsandgunsmithing]

The higher they jump, the sweeter the Breeze!

Why? Maybe...but why?

 

[Kracken McGraw]

Why? Maybe...but why?

Oh heck that’s just an old cowboy bronc riding saying I was throwing out because it was halfway comical in reference to what was said!

 

[gunsandgunsmithing]

Oh heck that’s just an old cowboy bronc riding saying I was throwing out because it was halfway comical in reference to what was said!

My head was stuck on the subject. Sorry. I can see the humor though, even though it might not show in text.

 

[sdbob]

What ever you do it must be consistent. Lets face it, if the shoulder isn't in the same place each time the bullet won't be in the same spot in the lands and that will cause vertical