Shoulder Bump Issues

[358WCF]

I'll give that a try. Lets say that the wear does show towards the bottom of the case... what might that indicate is the problem?

Minimum spec chamber? Maximum spec brass? Combination of the 2? Out of spec dies? Rare but it happens. At least you'll have an idea of where the problem is to correct it.

The CIP (the Euro equivalent of SAAMI) dimension at the (approximately) .200 line is a few thou larger than SAAMI spec for 308 & 06 based cases... maybe for other cases too?

Norma (from Europe) may still make Nosler brass for some cartridges.

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cip-bobp.org

There may be newer SAAMI specs but this was saved in my comp.

https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf

Isn't this fun? We're all yahoos (or bozos) on this bus.

 

[Eagle Six]

I'm not that familiar with 300 WSM. Looking at your 200 line measurements compared to @quest450 my initial thought would be as @358WCF, you may benefit from a small base die. If it were me I would go back to post #3 (again @358WCF) with a blue sharpie I confirm 200 line is the interference.

 

[LHSmith]

Loads are on the higher end of tolerances but not out of line or showing signs of too much pressure.

Perhaps more pressure than you think. Norma is on the soft side and not annealing doesn't help. Six times reloaded is asking a lot if the chamber to die match-up is not optimum.

 

[Sandstorm]

Send your 2 or 3 time fired brass in and have a custom die made. Also get new brass.
This is your issue. Your brass is expanding further than your die will size it back.
Been there before. just my 2c Sir.
Tell your Machinist your issue at the .200 line and he will know.

 

[copperking81]

You could get a small base die or get a cheap Lee die and cut the top off so it doesn't size the shoulder then grind the bottom until you get the size reduction you need.

who makes the smallest 300 wsm die (base size)

pretty simple who makes the smallest dia base of the current production sizing dies. my current die , a redding, is not quite small enough to get a true bolt free drop. a very minor closing is required and works but i would like to get smaller without getting shorter thanks

forum.accurateshooter.com

That's a good thread, thanks for sharing! I might give the Wilson a try. Sounds like that fixed a similar problem he had.

 

[Henryrifle]

Any possibility you are pushing/pulling a mandrel through the necks after you measure your sized brass and the mandrel is pulling the neck & shoulders back up?

Hank

 

[243winxb]

When I measure at the 200 line (a new concept / term to me... thanks), I get the following...

• Fired brass, shoulder bumped .002 (chambers very tight) = .553
• Fired brass, shoulder bumped .020 (chambers fine) = .551
• New unfired brass (chambers fine) = .549

SAAMI drawing has the maximum loaded cartridge at .555" . The barrels chamber may be on the tight side?

Get a single stage press that uses a standard shell holder. When sizing, at top of the stroke, the shell holder should make full contact with the bottom of the Fl die.

Your current setup should not allow .020" room for adjustment.

A standard die set up will provied around .005" shoulded set back.

 

[L.Sherm]

Watch Alex's video on shoulder bump with the stripped bolt method, Eric Cortina has a good video about his new dies that he shows how to do it and why not to trust just measuring a fired case and just subtract .002.
Are you using a .450 comparator?

 

[K22]

What got my attention was the aftermarket barrel. It may not be cut to SAMMI spec which commercial dies are set up to size for.

Check the chamber with SAMMI go / no go gauges. On the surface, this sounds like the die is not compatible with the rifle chamber.

I agree, you need to get the root cause of this issue. I would consult an experienced rifle smith and have the chamber inspected.

 

[okie]

GUFFEY!!!!!!

 

[Jonnyofalltrades]

or get a cheap Lee die and cut the top off so it doesn't size the shoulder then grind the bottom until you get the size reduction you need.

Wow! That's a great way to work around having a die that's fatter than your chamber. I currently have a 7mm rem mag that does this with the Hornady die that I use for it. I was considering buying a small base die, but that sounds much cheaper and easier.
For those without metalworking tools, maybe not so much...

 

[243winxb]

Your current setup should not allow .020" room for adjustment.

Has any corrections/equipment been made/changed?

 

[copperking81]

Has any corrections/equipment been made/changed?

Not yet. I sent the die back to Redding to analyze and I'm waiting to hear back. That's where I'm at.

 

[Webster]

I have a 300 WSM that after shoulder bumping fired brass back .002 inches with a FL sizing die, is still a pain to chamber. In fact, the resistance doesn't start to feel normal until I take it down .020 inches shoulder bump (fired = 1.730. Sized to comfortable chambering = 1.710). I'm measuring with a Sincliar bump gauge and digital calipers. Rifle is a Model 70 with a Bartlein barrel. Loads are on the higher end of tolerances but not out of line or showing signs of too much pressure. Die is a FL Redding.

Thoughts on why that might be? The gun will chamber with the minimal bump but it takes some effort. My biggest concern is I don't want to gal the lugs or damage the gun.

Measure expansion at the .200" line. Try a lighter charge.

 

[copperking81]

Redding got back to me. Along with the die, I sent them three sample sets of brass... 1) two fired unsized cases, 2) two fired and sized cases shoulder bumped back by .002 and would not chamber and 3) two fired and sized cases with the minimum shoulder bump required to chamber (bumped by .020). I took these measurements with two different calipers using a Sinclair bump gauge insert.

Redding measured the cases with an optical comparator and got different measurements than I did...

1. The sized cases where I measured the shoulder bump as .002 had actually had grown in length after sizing. Apparently that can happen if the die isn't seated far enough. I wouldn't have known because my measurements showed .002 inch bump and to the naked eye, the die looked pretty close to seated.
2. The sized cases where I measured the shoulder bump as .020 were only bumped back by ~.007.

I think the net of it is, there is an issue with my bump gauge insert. I'm going to buy a Hornady bump gauge and see what results that produces.

 

[243winxb]

SAAMI datum is .445" The Hornady Cartridge Headspace Gauge Bushing is .420" Doesnt seem like a good match?

But never used a bought one. Going for a crush fit on bolt closing, good enough for my factory rifles.
Never removed any bolt parts.

 

[josebd]

you might need a small base die?

 

[6BRA]

Buy once cry once...save yourself more headaches and get a SAC comparator.

 

[copperking81]

Buy once cry once...save yourself more headaches and get a SAC comparator.

Are malformed comparators a regular problem? I'm not opposed to spending the money on quality comparators. I assumed the Sinclair branded were likely pretty good.

 

[6BRA]

Are malformed comparators a regular problem? I'm not opposed to spending the money on quality comparators. I assumed the Sinclair branded were likely pretty good.

These will fit your case shoulders very well. JMO The will in turn center the brass on your caliper effortlessly.