9mm OAL

[Mort61]

New member, long time THR observer here. A little history: I've been reloading 30-06 and 44 mag for more than 20 yrs on my Rock Chucker but just started 9mm less than a year ago. I've been trying to work up an accurate load for my LC9S and Security 9's that my wife and I have. I've read wonderful things on this forum about RMR JHP 124gr and Power Pistol and I have these bullets and powder on hand. I'm really struggling to find what my guns like. Other bullet/powder combos seems to perform better for me.
Now my question: I've read on this forum some of you folks will work up your loads to some point and then start playing with the OAL. Some claim it really brings things together. I look at my Hornady 11 and Lyman 50 and they're OAL is 1.060 at max 5.6- 5.7 gr PP. My Speer 13 lists max 6.4 PP and OAL of 1.120. I've read PP likes to be run toward max
How much can I vary the OAL with given charge?
I'm sure small changes are the rule, but what is considered "small"?

 

[kcofohio]

I don't know if there is a real answer for that. Some powders are more sensitive to case capacity change then others.
Best to work up a new load for different bullets.

 

[LiveLife]

what is considered "small"?

For pistol loads for me, 0.1 gr of powder charge and .005" in OAL.

Mainly because that's the variance most pistol powders/measures will throw and OAL vary by depending on the press and consistency of bullet ogive used.

 

[LiveLife]

LC9S and Security 9 ... RMR JHP 124gr and Power Pistol ... really struggling to find what my guns like. Other bullet/powder combos seems to perform better for me.

This is what I use to identify the most accurate load for particular bullet/powder.

Determine the longest Max/Working OAL that will work with your pistols/barrels/magazine and conduct powder work up from conservative start charges until you identify the charge that produces smallest groups.

Then if you are not at max charge, incrementally decrease the OAL (by .005") to see if group size decreases. If group size decreases, use shorter OAL. If group size doesn't decrease, use longer OAL.

 

[Mort61]

LiveLife, thanks, that helps a bunch. Gives me something new to try

 

[Cemetery21]

Just a reminder that those "book" OALs are for specific bullet shapes. You need to find out where your bullet hits the rifling to know the max length, then verify it will actually feed in your pistol. Bullet shapes vary widely between makers/styles and that affects the OAL your barrel will tolerate.

 

[Mort61]

Ok, but my XTP is .571 ish long and my RMR JHP is .549 ish long and a GDHP is .561 ish long. If I would load these to the same OAL, based on plunk test,, over identical powder charges, it seems to me I would develop much higher pressures with the XTP bullet than the RMR because more bullet is inserted into the case.
Granted, the bullets are different shapes but when I find the magic OAL for my guns I want to take that variable out of the equation, if possible. Am I thinking to hard about this?

 

[LiveLife]

If my Working OAL (bullet seating depth) is significantly shorter (deeper) than published, I consider reducing start/max charges by .2-.3 gr.

 

[Cemetery21]

They will each plunk (bullet touches rifling) at a different OAL due to the shape of their nose. To follow LiveLife's advice, you need to "Determine the longest Max/Working OAL that will work with your pistols/barrels/magazine and conduct powder work up from conservative start charges until you identify the charge that produces smallest groups.".... per each bullet design/shape.

 

[Mort61]

Ok

 

[murf]

your plunk test for each of those bullet types will be different. always start at the bottom of your load data and work up. you may want to stick to hornady load data for the xtp as the bullet skirt is unusually long. use a dummy round for each type of bullet. there is no "magic" oal for all bullets.

luck,

murf

 

[Mort61]

Yeah, I'm starting to come to that realization. I'm just looking forward to going to the range with a couple different loads that are "in production" rather that a dozen different loads that are under development . It's definitely enjoyable and rewarding but might get pricey paying for the range time.

Thanks to all for your help

 

[Cemetery21]

It depends on your end goal. If you want to tweak the last 1/8" of accuracy out of a bullet/powder/brass/primer combination, or if you just want to produce a load that will group within your ability to shoot. A whole lot of people can't shoot the difference between an OAL of 1.15" vs 1.10"

 

[Mort61]

I'm not looking to drive tacks with my 9s. I just want to improve my ability as a shooter. If I can make good, consistent ammo then I can concentrate on my ability, or lack thereof.

 

[wtf808]

Give the GRT (Gordons Reloading Tool) a shot, it can give you a general idea of how different components affect shot performance. You can tweak powders, bullets, oal, etc..
https://grtools.de/doku.php

If anything it gives you a decent starting point for your loads..

 

[mdi]

It's rare that a good load, "The Load" is found without a load work up. I would (and have done many times) find a load in my manual, purchase components, use starting powder charges as per my manual(s) using the book OAL. After I find a promising load, I may vary a bit (up or down charges by .2 gr. , and lengthen/shorten OAL.005"). Has worked for me for, as far as I can remember, with every handload for all my guns for 35+ years...

 

[joneb]

I load the RMR 124gr MW at 1.08" I could seat longer or shorter but this depth works well with Be-86 in my Sig p-938.

 

[jmorris]

I'm really struggling to find what my guns like. Other bullet/powder combos seems to perform better for me.
Now my question: I've read on this forum some of you folks will work up your loads to some point and then start playing with the OAL. Some claim it really brings things together.

What are the results you are currently getting (furthest two apart, from what number of shots, at what distance) and what are your expectations?

 

[lordpaxman]

Other bullet/powder combos seems to perform better for me.

I usually load the RMR MPR at 1.120” with a faster powder than PP. What other powders do you have? While I like the flash and bang of PP , I’d rather have it a bit quieter.
If you have other loads you like better, what are they?

 

[Lennyjoe]

Ah but remember one thing, all barrels don’t “plunk” the same. If your building a load for use in multiple 9MM,s I’d recommend plunking each with your bullet choice and document the shortest OAL for future development. CZ’s come to mind in this case…

 

[LiveLife]

I usually load the RMR MPR at 1.120”

Ah but remember one thing, all barrels don’t “plunk” the same. If your building a load for use in multiple 9MM,s I’d recommend plunking each with your bullet choice and document the shortest OAL for future development. CZ’s come to mind in this case…

+1

From the link of Max/Working OALs for RMR 124 gr MPR JHP - https://www.thehighroad.org/index.p...col-for-reference.848462/page-2#post-11465109

• SIG P320 X5/Bar-Sto Match 5" Barrel - 1.03"
  
• Glock 23/Lone Wolf conversion barrel - 1.04"
• S&W Shield EZ - 1.040"
• Taurus PT-809 - 1.040"/1.030"
• Glock 22/Tactical Kinetics conversion barrel - 1.055"
• SIG P938 - 1.06"
• HK VP9 - 1.08"
• Taurus PT-111 G2 - 1.085"/1.070"
• Canik TP9SFX - 1.090"/1.070"
  
• SIG P320 X-5 - 1.10"
• S&W Shield - 1.105"
• Glock 22/KKM conversion barrel - 1.115"
• Beretta 92FS - 1.125"
• Browning Hi Power Mark 2 - 1.125"
• SIG P226 Legion SAO - 1.150"

 

[Mort61]

I was off the grid for a few days. Wow, lots of comments. Both guns shoot factory ammo very well. By that I mean I'm shooting 2" ish @ 10 yds with 5 shots and I have the bullseye surrounded. I am getting similar groups with some of my reloads, but they'll group 4-6" away from the bullseye. Sometimes left, right, up down. Some loads will spray em all over. And I haven't found a recipe yet that will put both guns in the same group. I have a few loads with a bit of success:
4.8 gr 231, berrys 115 prn. 1.135 oal
4.0 gr titegroup, rmr 124 jhp, 1.060 oal
5.0 gr br-5, berrys 115 prn. 1.140
4.8 gr br-5. Berrys 124 prn, 1.140

I'm confused why my groups move dependant on the components. I don't seem to have this phenomenon with my 44 mag.
I'm not trying to win any competitions but I want to get to the point where I shoot better. I understand the components will each need their own development. I hope.its possible to get each load to hit in roughly the bullseye area.

 

[lordpaxman]

Hopefully your guns have adjustable sights of some kind. Heavier bullets will tend to impact higher than lighter ones with semi-autos, but I’ve never seen any consistency in how much and with all guns. I also haven’t seen 4-6” deviations at 10 yards, but that’s only my reloads.
As suggested above, determine your max COL for the RMR MPR. I would first try W231, a faster powder than PP, at a near max COL and see how that does. If you’re having better luck with faster powders, try those first.