Incorrect specs on RCBS sizing die?

MassHunter32

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I'm wondering if the folks here have experienced this or perhaps can point out I'm missing something obvious. I've loaded thousands of rifle rounds, but only recently started loaded pistol. I've done a few hundred 45acp and 9mm with no issue, but I'm having trouble with my 40 S&W (yes, I'll take the abuse on that).... but what can I say I love my HK P30L in 40 S&W.

I bought new the RCBS 3die carb TC set for .40 S&W/10mm auto. I deprimed and clean separately and I'm loading on a single stage RCBS press.

Set up on sizing isn't that difficult and this is where I think my problem is with the die. I seat the die as the instruction say on the case holder and don't over cam. Only did one and when I went to start the next die set up, I noticed the bullet head already fit in the case. I put the sized case in the case checker and about 1/8 inch won't go in. Tested it in my barrels and same 1/8 inch sticks out. Checking on the calibers the spec on 40 say I should be at .424 but I'm at .425. I decided to run 5 more across different once fired brass (assorted headstamps) and getting the same results. About 1/8 inch of case won't go into barrel or case checker and I'm running at .425, .4255 at the base.

I can't run the case further into the sizing die, since I'm already touching the die and case holder. FYI...using the same brand and carb set for 45acp and 9mm with no problem.

Am I missing something or could I have a die that is simply machined out of spec? Appreciate any thoughts, before I contact RCBS.
 
Lee bulge buster will solve this if your RCBS is actually within spec.
Can you get some measurements off of the die for us to cross-reference another die set?
Where did the brass come from? Range pickup? Could be a case of glock bulge.
If it's your own brass from the HK P30L, if so, do they have an unsupported chamber? I have a P30SK, im not sure the differences between the models.
 
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I too was going to ask about the shellholder too. I know some have been known to grind some off the top flat on a shell holder to get their die to work optimally. Usually appears when using a different brand shell holder versus the die.

Also check some fired cases, fired from your gun, or range pick ups, and check them in your barrel and also record some measurements using the calipers. Then try them through the die and repeat checks/measurements.
 
Lee bulge buster will solve this if your RCBS is actually within spec.
Can you get some measurements off of the die for us to cross-reference another die set?
Where did the brass come from? Range pickup? Could be a case of glock bulge.
If it's your own brass from the HK P30L, if so, do they have an unsupported chamber? I have a P30SK, im not sure the differences between the models.
Traveling right now. But sure I'll measure the die. Brass is all mine (I put down a blanket when I'm just shooting at the range). It would be a mix (mostly Blazer and Win) shot from MP40 and HK P30L.
I have never heard of an unsupported chamber. I'll have to look that up. I can say and probably should have put this in the write up also. I can put the "unsized" fired brass back in both barrel chambers. But once I run it through the sizing die.... no good. the last 1/8th sticks out.
 
Run a set of calipers across 3 or 4 points on the case between the mouth and the head after you re-size it.
Should be the same diameter all the way down.
thanks I'll give that a try. I think I did it for one or two (traveling today)... but only at the top and bottom. They were different. Like I said above, the bottoms were .425 & .4255... if I remember the mouth was .424.
 
I too was going to ask about the shellholder too. I know some have been known to grind some off the top flat on a shell holder to get their die to work optimally. Usually appears when using a different brand shell holder versus the die.

Also check some fired cases, fired from your gun, or range pick ups, and check them in your barrel and also record some measurements using the calipers. Then try them through the die and repeat checks/measurements.
Fired cased do go back into the barrel, problem shows up after sizing die. I'll run some before and after measurements when I'm back. Thank you for the ideas.
 
Had the wife send a picture since I'm not home. It appears the the ring is recessed a little because there is maybe a 1/32 bevel right at the mouth
Are you sure its a 40 die?
What press?
is your press ram at its highest point.?
Not the arm all the way down but the ram at its highest point.
 
Thought I would give an update. First, thank you all for the replies... I learned tons of new stuff...case bulge, unsupported chambers etc... I put a call into RCBS and heard just about all the same information with a few specifics. Questioned right away on if I was using a glock and said no MP40 and HK P30L. They confirmed that they have had calls from people using MP40s that have this issue with the brass. Although they wouldn't "recommend" their competitor, they said they have understood the Redding GRX die has resolved the issue for MP40 shooters (same one trashcandan referenced above). At this point 95% plus of my brass in out of the MP40, since I just picked up the HK recently.

They had no specific knowledge on the HK and recommended that I try to check the difference on the fired brass. At this point I would have no ability as it is in the same bucket, but will keep them separate on the next range day. It may just be another reason to like the HK.

Thanks again and it may be awhile before I get to shoot the HK at the range but I'll try to keep this updated for the next person if they have the same troubles.
 
Are you sure its a 40 die?
What press?
is your press ram at its highest point.?
Not the arm all the way down but the ram at its highest point.
Yes on 40... for everyone it is code 22115 on the set, but at this point seems to be an issue with the MP40
Using a Rock Chucker press and absolutely at the highest point and case hold (#27) touching bottom of sizing die.
 
Thought I would give an update, just in case it can help someone else down the road. Had the opportunity to sit down and go through the brass and measure items and sort this out.

I would say everything comes down to tolerances. The two biggest tolerances in question are the chambers of the S&W MP40 and HK P30 in 40, as well as, the case checker(s).

I can now safely say that neither the HK nor S&W have an unsupported chamber. I will say the S&W’s chamber is slightly larger than the HK and this is where “the problem” (which I don’t believe turns out to be that much of a problem) lies.

The brass from the S&W (when fireformed) and then run through the above mentioned RCBS dies…. Produces rounds that do not all fit in the Lyman 40 cal case checker and don’t smoothly all fit in the HK chamber. All rounds fit back into the S&W.

All reloads would go into the HK chamber and eject, however some were “tight”. The tight ones were mostly nickel plated and had a thicker case wall.

I purchased a RCBS case checker and found it almost 5 thousandths larger at the mouth (RCBS opening - .425, Lyman - .4205).

Every reload with the RCBS set up functioned in both the S&W and HK, however 50% didn’t go into the Lyman case checker. All but 2 fit into the RCBS. The difference again seemed to be case wall thickness and brass from the S&W.

With the Redding die (went with carbide), All brass fit into both case checkers and both guns.

Morale of the story….. to me at least. If I had started with the RCBS case checker, I would never have realized this “problem”. All of the rounds functioned fine in both guns. Using the Redding die does seem to ensure the brass goes all the way back to "new" dimensions and would seem to limit the possibility to get a FTE.

Thanks again for all the above advice.
 
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