New Member with a Measurement Question

[89Buffalo]

So I got my RCBS RockChucker reloading press out of its 15 year hiatus and proceeded to make some non-powder/primer cartridges in order to reorient myself.

I used once fired brass (PMC 9mm 158g subsonic), 124g GA Arms 9mm FMJ, with the RCBS 3-die set. All brass was within normal limits (WNL), per 0.001" Vernier callipers, so no trimming required. Also fit flush in a Dillon 9mm shell gauge.

After decapping/resizing all brass was WNL and fit flush in the Dillon. Same as well for post neck expanding, WNL/fit flush in case gauge.

However, following bullet insertion and prior to taper crimp, the cartridge would not fully seat into the shell gauge (inserted down to the extractor groove) though the calipers showed no deviations.

Taper crimp offered no solution.

I should note that the final dummies fit well into the 9mm barrel (S&W M&P 9mm Shield) that fired them, as well as cycled from magazine to extract. However, they did not seat in a 9mm EFK-Dragon barrel (H&K USP 9mm Compact 40 [conversion barrel]) as deep as the original barrel, nor did they fit flush with the shell gauge. Additionally, the cartridges would not cycle through the H&K.

Please note that according to my vernier caliper, all measurements are WNL. So why not fit the case gauge or EFK barrel?

What do you think? Perplexion City! THANKS

 

[spclark]

What’s the bearing surface OD behind the ogive of those 124g FMJ’s? Without looking over your shoulder I have to guess they’re bigger than the PMC bullets you’ve successfully fired in both barrels?

You have any PMC left you can pull a bullet from, measure its bearing surface OD?

That Dillon gage doesn’t have a throat or leade like a barrel’s chamber so even if they have a different shape ogive they ought still to work. But seated in your sized cases the result is just too wide to chamber properly.

 

[Mikemci]

Agree with spclark. Your new bullets have a larger pressure ring than your older ones. Especially if a flared case fits your gauge/chamber.

 

[89Buffalo]

The 124s ave 0.355" with no deviation out of 8 bullets, whereas the PMCs ave 0.354" of 8 (0.353" - 0.355").
I have not fired the PMCs with the H&K EFK barrel.

 

[Mikemci]

Have you checked the two barrel diameters?

 

[89Buffalo]

I haven't checked barrel diameters. I did, however reload another dummy using the same once fired PMC brass but with a Spear 124g Gold Dot hollow point. The final product does fit the case gauge flush, as well as the S&W barrel. It does not seem to fit the EFK barrel, which has in the past accepted factory cartridges.

 

[Mikemci]

It's a diameter problem, so only a few possibilities.
1) Larger bullet
2) Smaller barrel
3) Over crimping and "wasping" the case
4) Etc.
Keep investigating, you'll find the answer.

 

[89Buffalo]

Based on what I have now, I am thinking the issue may be the EFK barrel chamber diameter. I will contact them to discuss the possibility. I really hate to question them as they probably have way more knowledge as I. Additionally, it may be me or my reloading techniques.

I actually crimped the GA Arms bullets a bit more (VERY little) and they will fit both the original S&W and the case gauge, with a very little nudging (Note: I did crimp another further, but to no advantage).

Is commercial ammo manufactured less than the max to ensure it fits all chambers, because as I stated earlier, the virgin PMC cartridges do drop into the EFK barrel, S&W barrel,as well as a flush case gauge fit.

 

[ronemus]

If you flare the case mouths too much with the expander, your crimping die may leave a section behind the case mouth with a larger OD (tulip profile for want of a better description. You only want to expand enough that you can seat the bullets without shaving off jacket metal.

 

[89Buffalo]

Yes I expand to a minimum, Good thought!

 

[Daddymac]

Based on what I have now, I am thinking the issue may be the EFK barrel chamber diameter. I will contact them to discuss the possibility. I really hate to question them as they probably have way more knowledge as I. Additionally, it may be me or my reloading techniques.

I understand what you're saying, but don't be afraid to call, and don't view it as questioning them as much as asking for help or info, the manufacturers are usually eager to help, and I have had some real, "oh, now I get it" moments while talking with them.

 

[Lone Hunter]

I did not see where you said you have fired any factory ammunition in the EFK barrel. Have you tried factory ammo in it and if you did were there any problems? Usually, it is the die set up and not the barrel. If it cycles factory ammunition set your die up with a factory cartridge including oal

 

[89Buffalo]

Yes I have use factory ammo as well as factory reloaded stuff...not a problem. But I'll try your idea.
Thanks