Pistol ladder question

[stagpanther]

I posted a thread about testing my latest homebrew 10 mm but there was no response--so I'll ask a more generic version of the same question.

Given barrel lengths of say 4 to 7.5" is it common in load development tests for pistols to exhibit similar nodes in accuracy that one might expect in rifle cartridge development? I ask because my tests were generally very wide groups but one charge came together dramatically close compared to the other ones. My intuition is that much of this might have been attributable to poor technique on my part--but it does seem a bit odd that a 5-shot group came together pretty well and then the rest opened up.

[chris in va]

I'm no expert, and the other guys will give better info, but it seems logical that various powders and charges can affect accuracy. Pistols are simply shorter versions of rifles, albeit with a lot more 'slop' factors thrown in such as barrel/slide fit etc.

[Nick_C_S]

I'm no expert either. So I'll just speak from my experience:

Pistols have accuracy nodes too. But I suspect (I'm not a rifle loader/shooter) the nodes are more subtle and are often obscured by other variables.

I load a lot of 38 Special and 45 ACP - so they're my best point of reference (I load a lot of 10mm these days too; but I need more data before I can speak to it). And yes, there are certain loads that "settle down" compared to the loads on either side of it and have low Standard Deviations. So the phenomenon sure seems to exist.

[stagpanther]

Thanks guys--my previous experience reloading for pistol was restricted to 41 and 44 mag for my blackhawks and I didn't seem to get as much variation when shooting that close to the target--another strange thing is that the tightest group for my 10mm happened sorta in the middle of the powder charge range--that rarely happens with any other load development I've done where typically I'll find nodes near the top and bottom of the charge weight ranges--and maybe 90% of the time the best node is somewhere in the top 80 to 100% of the charge weight range. I guess I'll probably just do the same ladder over again to see if the same thing happens.

[Mike / Tx]

I have loaded a bunch of handgun rounds over the past 35'ish or so years and there are some things that compare and some that just don't seem logical when they pop up.

There are quite a few powders which will overlap in velocities but when switching to one or the other simply hitting the same velocity doesn't necessarily mean you will find accuracy there. It might be a bit faster or slower and is mainly due to the pressure curves. Sometimes you can simply switch bullets of the same weight and hit something using the exact same charge weight you had tried before and drill the bull out where previously you shot a pattern.

With revolvers and I am guessing with auto's as well, the crimp can make or break accuracy as well. Too much and you spread things out and too little you don't get consistent pressures with some powders. It does pay to tinker with your crimp starting just light enough to hold the bullet in place under recoil and then adding ever so slightly a tiny bit more simply to see if things improve. Usually however if you have good case neck tension on the bullets you probably won't notice a ton of improvement in accuracy except with the slowest type powders.

[stagpanther]

nice, thanks.