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Discussion Starter #1
Here's what I got.
Hornady 124gr. XTP with 4.4gr. HP-38 and OAL is ~1.072.
Shot 24 rounds from a bench rest at 4 targets from 25 yards.
Accuracy sucked.
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So my question is, with a certain charge does OAL affect the pressure and velocity?
This is nowhere near the accuracy I got with my loads using 5.8gr. HS-6 and OAL of 1.065.

25yardbench-1.jpg

I have 50 more rounds with the HP-38 load, should I shorten the OAL?
 

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Yes OAL does affect pressure & velocity
I've loaded the 124gr XTP to 1.060 using HP-38 & TiteGroup
I've noticed with some pistol powders accuracy increases as the charge goes up
I would try OAL of 1.060 but start your loads from the beginning and watch for pressure signs
 

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Discussion Starter #3
OK. Just wanted to make sure I wasn't going to do something dumb.
I'll seat a few bullets a little bit further and see how they shoot.
 

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accuracy may improve or get worse?
thats the thing about reloading is the ability to make minor changes that affect both accuracy and dependability.
any reduction in OAL will increase pressures because it reduces the capacity of the case.
same thing as using a longer projectile in the same weight!
different primers may make a difference as well, really any changes can/ may make a difference either good or bad.
generally if you are not near a max load a minor change in OAL is not likely to be real dangerous but as mentioend its best to start low and work up with a shorter OAL.
really small cases like the 380 i am real concrened with OAL and there is little fluctuation in a min or max charge, but normally the 9 mm has more wiggle room.
 

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Discussion Starter #6
Exact load is hard to find.
I've seen from 3.9 up to 4.8 for the XTP with HP-38.
I'm using 4.4, so i should be in the middle of whatever is the real min and max.
Warmer weather coming, so I'll try the ones I shortened to 1.06 from 1.072.
If these don't work, I'll go to 4.6 on the next 100.
 

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OK. Just wanted to make sure I wasn't going to do something dumb.
I'll seat a few bullets a little bit further and see how they shoot.
I don't know a lot about reloading, but my understanding is your bullet crimp has a lot of effect on accuracy.
 

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the more crimp, the higher the pressure (brass holds onto the round longer). normally some crimp does increase the accuracy of the rounds, but you need to go slow because crimps can raise pressure fast if you go crazy with it. shorter Over All Length NORMALLY means higher pressures, but that depends on the case length and the length of the bullet, if the case length is short and the bullet is short, the case doesn't have as much contact with the bullet and doesn't hold on as long (this usually only applies if your crazy about your rounds and EVERYTHING has to be exactly the same. most of those people are the ones trying to shoot rifles 800+ yards and such)
reloading is all about finding what works for your gun, as what works great in mine may not be the best in yours. The manufactures recommend that whenever you change something about the load, you start at the minimum powder load and work up, but keep good records of what you make, and make fine adjustments as you go to get the best load possible for your gun. i usually will load enough to go to the range and keep track of how well it shoots, then when i get back write it in a book so that when i start the process over, i have it all in front of me to go over. some people will try 50 or 75 rounds of one adjustment and the same amount with another, but it can get confusing if your not careful with your data.
 
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Discussion Starter #9
Found what works best for me with the Berry's PHP 124gr.
4.3gr. HP-38 and OAL 1.04".

4-8-2012-Shootout1-2.JPG
 

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its intersting trying to figure out what amount of accuracy that one wants in a projectile.
while accuracy is usually a lot easier with a rifle especailly using a bench and bags, to see decreases in group sizes and how the group moves around the bullseye.
when looking for ultimate accuracy then everything needs to be as identical as possible.
many of the things that shooters of rifles do is just not prectical for a hunter and certainly not for a pistol shot as most all of us can not come near the accuracy of the gun or bullet in a pistol, the accuracy difference in most of us is human error.
so there is a difference in a pure target shooter and a person that wants to enjoy shooting and looking for personal protection.
Generally a uniform crimp will add to accuracy in about any pistol cartridge at longer distnaces, inside 20-25 yards I doubt if you can tell much difference.
JMO.
 
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