Loads useing reduced OAL

[Artemas2]

I ordered some Berry's for the first time because it is close to the profile of Hornady's HAP round, but for half the price.

Berry's lists the OAL at 1.169, Hodgon lists is for 1.150. I can't get a round to "plunk" and spin until 1.118. Still won't pass a case gauge until 1.075.
In case it was the crimp I slowly increased and rechecked it until it was clearly over crimped.

Hogdon lists a powder charge for 3.6-4.1 for that 1.150 length with unicorn .750 length brass.
Can/how do I safely guesstimate a starting load for an OAL that is .094 shorter than any published data? Am I safe to start with the 3.6 or do I need to go lower still given the substantial difference?

Berry's 124 Target Hollow point https://www.berrysmfg.com/item/bp-9mm-356-124gr-thp
Primer: WSP
Powder: Hogdon Titegroup
Brass: Range pickup, large length variations

[LittleLebowski]

Not sure of the book answer, but I have done nearly the exact same thing. You can back off to 3.5gr if you're worried.

[GuanoLoco]

Still won't pass a case gauge until 1.075.

#1: That doesn't make any sense to me - SAAMI spec is 1.169 IIRC and a 9mm case gauge usually doesn't care about OAL.

[GuanoLoco]

Hogdon lists a powder charge for 3.6-4.1 for that 1.150 length with unicorn .750 length brass.
Can/how do I safely guesstimate a starting load for an OAL that is .094 shorter than any published data? Am I safe to start with the 3.6 or do I need to go lower still given the substantial difference?

It's never a bad idea to start low. 1.118 isn't really all that short as far as short loadings go, I've had Stock 2 barrels that needed 1.085" with certain bullets (Bayou 135gr IIRC).

Going shorter is a non-linear proposition. Reducing OAL by 0.01" doesn't amount to much pressure-wise and velocity-wise at 1.150. Reducing OAL by 0.01" at 1.085" and shorter will mean a much larger increase in pressure - and may STILL not change velocity all that much. I don't think you are anywhere near danger territory though.

I suggest starting low, maybe even 3.4gr and going up - it doesn't cost anything but a little time and some cheap components. In general I start low, using the soft primers I have available (usually Federal), then monitor for pressure signs (primer flattening / flow / cratering / piercing) and velocity as I gradually increase the charge until I hit my goal.

[Artemas2]

#1: That doesn't make any sense to me - SAAMI spec is 1.169 IIRC and a 9mm case gauge usually doesn't care about OAL.

Got me. Cases all measure that same at .746. "Pass" also seems to be a loose term for me at this point.

[farscott]

Are you full-length resizing the cases? I suspect the combination of the tapered 9x19 case and some case bulging from barrels with less than optimum case support are combining to create your issue.

In any event, I would start with less powder. If the case volume is reduced by some percentage of capacity, I would back off the powder by the same percentage. In this case, the math appears to say the reduction is 8%.

[GuanoLoco]

Are you full-length resizing the cases? I suspect the combination of the tapered 9x19 case and some case bulging from barrels with less than optimum case support are combining to create your issue.

In any event, I would start with less powder. If the case volume is reduced by some percentage of capacity, I would back off the powder by the same percentage. In this case, the math appears to say the reduction is 8%.

My point is that the math isn’t linear - there can be little difference at long or medium OAL’s but HUGE difference at very short OAL’s.

I’ve seen commercial 9mm loads as short as 1.05x” so short is relative with 9mm.

I’ve use the Lee U-die to help with case gauging issues but it is too hard use use by hand and works the brass too much - I get too many case splits. I’m currently using a regular Lee full-length resizing die for pre-processing many 10’s of thousands of cases (30-40K0 just in the last month or so.

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My case gauge failures with a BSPS Hundo Case gauge are about +/-1% with mixed range pickup brass, using a Dillon taper crimp die and a crimp of aboout 0.378-0.379”.

[farscott]

My point is that the math isn’t linear - there can be little difference at long or medium OAL’s but HUGE difference at very short OAL’s.

I’ve seen commercial 9mm loads as short as 1.05x” so short is relative with 9mm.

In general, I agree with your point that the relationship is not linear. The math is a good place to start as one should reduce at least the amount of the capacity reduction. In other words, a sanity check.

[revchuck38]

I’ve use the Lee U-die to help with case gauging issues but it is too hard use use by hand and works the brass too much - I get too many case splits. I’m currently using a regular Lee full-length resizing die for pre-processing many 10’s of thousands of cases (30-40K0 just in the last month or so.

I've been using the U-die with my RL550 and haven't noticed it to be too hard, but then I'm not processing 30-40k/month. I was using the standard Lee die until I broke the decapping pin and found there was little difference in the prices between a new die and a new stem. I think I've had one split 9x19 case in almost 40 years of handloading - I always lose them first.

[GuanoLoco]

My reloading processes are probably a bit rougher on brass. I preprocess (quick manual QC + size/swage/decap) all my brass before reloading at 2400 RPH on a Mark 7 / 1050. I can do this as a background task while watching NetFlix & doing minor chores like cleaning guns, polishing parts, etc.

During the reloading process (also 2400 RPH) I’m doing a 2-step flare (Mr. Bullet Feeder funned in a Lee Expander) in the swage station, then the Dillon powder funnel in the powder station. No NetFlix during this process - I’m busier than a one-armed paper hangar.

Why to 2-step process? I like running at max speed, getting done ASAP, and I really dislike fixing jams duiring reloading. I also find that this process minimizes bullet topple and other issues inherent in high speed loading.

BUT - I get issues like case splits, etc. that I never experienced when using less harsh manual loading processes. Then again, most of my QC failures and the lesser case splits shoot just fine as practice ammo.

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