Variances in shoulder bump?

[Murray Brook]

The only "issue" with the Redding Competition shell-holder is that, from press manufacturer to manufacturer, the tolerances of the press-ram:shell-holder slots vary widely!

Some brands will accommodate contact between the bottom face of the shell-holder body, causing a GAP between the ram-face and the head-space face of the shell-holder - make certain that when the shell-holder is installed, there is NO GAP between the ram-face and the shell-holder bottom rim.

If/when a GAP is present, the Redding Comp. shell-holders will NOT[necessarily] deliver the 0.002" difference in head-space, as the tolerance(s) for the shell-holder body and ram slots are not tightly held!!
When the correct surfaces mate, the 0.002" difference between shell-holders is pretty close. With the contact on the S-H body face, the difference my be anywhere from equal to, or, many 1/thousandths of an inch off.

For predictable/reliable shoulder-bump, of 0.002" form S-H to S-H is desired, lose the gap and assure enough contact to use-up any/all "slop" in the press linkages. If you simply use a single S-H and use firm contact, should achieve uniform bump - you'll need to adjust the die to achieve differing shoulder set-back.

If there is a visible, or, measurable gap, simply grind off the very bottom face of the shell-holders: couple of pics. RG

P.S. edited for clarity.

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Great post TKS. Clears up some things for me. Checked my Comp sets and had to grind/sand some.

 

[J.d. Popkes]

Best tip of the week.

Agree. Use Redding presses

 

[HawgBonz]

I dunno bout changing presses just to "try it". Seems a lil brash.
So yesterday I decided to step away from the 308 loading until a coupla things get here that I think may help with the neck tension regulation. Set up for 7mm PRC and had a lil pile of Hornady brass hangin around that needed sizing so I tried a slower, more deliberate stroke with a short pause at the bottom and a slow upstroke. According to the 420 comparator thru a lot of about 50 the bump only varied by .001". I'd have a hard time gettin my undies inna wad over that. And with that I could go back to using the LCGW trimmer which made life easier and more consistent. Finished up with a quick annealing. Got a load showing promise. I'll get back to the 308 shortly.

 

[JFrank]

According to the 420 comparator

This use to have a different meaning…

 

[HawgBonz]

This use to have a different meaning…

If I were to partake it may hep s'plain a few things.
Or at least lower the "expectations".

 

[JFrank]

If I were to partake it may hep s'plain a few things.
Or at least lower the "expectations".

You’re on a good path now with the sizing.
I think it would take a fair amount of variation to change a long range target or change the case pressure enough to see it on a chronograph.

 

[Webster]

Sample size 100 pcs.
I'm FL/bushing (Redding) sizing 308 Starline brass with 4 firings and they get annealed every pass thru. I use the same RCBS Summit with the same die that hasn't been unscrewed for the last 3 firings. Cases are properly lubed with a thin coat of sizing lube and checked with a .375" Hornady comparator. As fired they come out ~1.655.
I've tried to set the die for .002" bump but I can get no regularity from it. They'll vary from 1.654 to 1.650. I'm using the same stroke and trying to keep as uniform as I can but to no avail.
Is this just the cost of working cheap brass? Mebbe I'm not annealing enough with my lil induction unit? I heat it till the case mouth starts to glow slightly.
I've got some Peterson waiting for when I felt like I was back up to speed. But wanted to practice with this Starline cause I could better afford ta screw some of those up. Whatchya think?

What's the rifle used for?

 

[Oldbloke]

Lube inside the neck
Anneal often
Good case lube

 

[HawgBonz]

What's the rifle used for?

Right now the 308 is just kindofa place holder to play with till my "big boy" rifle is ready sometime in the next coupla/few weeks. Gobi's duty will be for beatin around, hogs and general plinking/ringing steel down on my lease to around 7 or 800y with the majority being under 500y. So ES won't be so much of a concern.
But I figger doing what I can now to try and learn will help when the "for reals" rifle comes online.

 

[D-4297]

After shooting Lapua SRP Brass for almost ten years , I recently purchased some Starline .308 SRP Comp Brass , and the very first thing I learned about it was that it is a "stiffer" material , and does require a slightly longer time annealing .
I added 3 seconds to my annealing time ; ( Anneleez ) and they Bumped to a consistent
-.001 of my chamber sizing . The second time , they all went to a "Bump" of .000 to my desired number .
Starline is a tougher brass , and does need a bit more heating time . I also adjusted the Flame on my annealer more towards the base of the neck and shoulder , and this seemed to take care of the inconsistencies in Bump length . It shoots as good as Lapua , and even allows the same load I used in my Lapua . Don't know if it will last as many reloads as Lapua , but I'll find out over time .