varying OAL with 45acp

Status
Not open for further replies.
F

firstg19

Member.
Joined
Apr 21, 2008
Messages
73
Location
MO
I am reloading 45acp using hornady 200gr fmj-ct encapsulated bullets, using 5.8 grains of W231 (hornady manual says staring grains is 5.7). It lists OAL at 1.245. Is it okay to vary OAL by 1.240-1.250, or is this too much? I have been spending too much time trying to get everything within 1.244-1.246, and I'm wanting to know if its okay to vary be a bit more?
 
Just know this you are already over charging the load which is fine once you test that load. So the shorter the OAL the more powerful the charge gets as well you really need to test the shorter OAL with the reccomended start load.
 
Longer is fine as long as it feeds in you pistol. For that matter 1.240 with that load would be safe as well. The idea is to not increase pressure by decreasing case volume. The difference between 1.240 and 1.250 will not cause a safety problem. It might change your POI though. Whatever length you settle on, try to be as consistent as possible. Make sure to write down the components and OAL in your reloading log.

You do keep a reloading log right? You will not remember from one reloading session to the next what you had settled on. Don't ask me how I know, I now write down everything reloading related.
 
Mags, he is starting at 1/10 of a grain above minimum. The "max load, use with caution" load for W231 and that bullet is 6.8gr so he has loads above his stated load to test before entering the danger zone.

Care should always be used when working up a load.
Make sure your scale is accurate and trust you scale. The difference between 5.8gr and 6.8gr of W231 sure doesn't look like much.
 
You will have no problem varying the AOL +/- .010". It's when you are going over this (+/- .010") or are loading at or near maximum powder charge that you will have problems...
 
Have you measured the length of several bullets to see if they are the culprit? Doubtful,but something is amiss somewhere.
I also think you'll be fine to continue on with that load and those variances as long as they'll feed/function for you.
 
Measure from the ogive!

You can't measure the OAL from the top of the bullet. It will vary a few thousandiths even with match ammo. You need to measure from the bullet ogive.

See Hornady or stoney point for tools.
 
Mr. Lee Said.................

If it is a Lee Press :D
Seating depth variations

There are a number of possible causes for overall length variation. One is the way it is measured. If you measure overall length from the tip of the bullet to the base of the case, remember to subtract the variation due to bullet length tolerance. The bullets will vary in length due to manufacturing tolerances (bullets with exposed lead noses are the worst in this regard) and this will add to the overall cartridge length variation. Remember that the bullet seater plug does not (or shouldn't) contact the tip of the bullet when seating, but contacts farther down the ogive. For a more accurate seating depth measurement, take the seater plug out of the bullet seating die, place it on top of the cartridge and measure from the base of the case to the top of the seater plug.

Another possible cause for bullet seating depth variation is seating and crimping at the same time when trying to apply a firm crimp to untrimmed cases. Variation in case length also causes variation in the amount of crimp applied. Long cases get a heavier crimp than short ones. When seating and crimping at the same time, the crimp is formed as the bullet is seated into the case. The crimp will form sooner on a long case, and therefore the bullet will not be seated as deeply. The solution is to seat and crimp in a separate step (the Lee Factory Crimp die is good for this) and/or trim cases to a uniform length.

The amount of force required to cycle a progressive press varies with the number of cases in the shell plate. When the shell plate is full, it is harder to lower the lever than when there are one or two cases present. This can lead to variation in cartridge overall length because there are different loads placed on the working parts of the press. When the shell plate is full, seating depth will be slightly long, because the load is higher and all of the clearances are taken up. With the shell plate nearly empty, the load is not great enough to squeeze out these clearances, and the seating depth is short.
Click to expand...
 
Just a bit of info from some 45acp load testing. Yesterday I tested 4 loads of Longshot (2 different charge weights, 2 different COL) and 2 loads of AA#5 (same charge but different COL). In all 6 loads there was NO difference on my chrono based on COL for the ones with the same charge weight. Different charge weights obviously had impact on velocity, but at least from just this data changes to COL had no impact on velocity. I also tested some 9mm and 40cal, both of those had significant changes in velocity with just a change in COL.

Now, I can't say what impact there was on pressure ... but I have to assume COL has little impact in 45acp or you'd see a velocity change. I can only assume this is because 45acp is such a low pressure round, 9mm and 40 are higher pressure and showed a different result.

Has anybody else seen this, or was it some sort of aberration?
 
I never understood why loads are worked up from OAL. I understand it from a you can't be to long or it will lock up the cylinder or wont fit in the mag, but what really matters is how far the base of the bullet is seated into the case. I guess its just because we have no way to accurately measure it.

If you have two 125gr bullets and one is .500" long and the other is .505" long and you seat them both to a OAL of 1.245" and there right on the money one bullet is actually taking up .005" more space in the cartridge then the other. Keep in mind that the human hair is a average of .005" thick or a thin sheet of notebook paper is .004" thick. It really doesn't matter that much to me as long as i'm within +/- .005 i would call it great. IMHO

Measure a factory box of ammo once and you will know why hand loads are more accurate then factory pretty quick.
 
Status
Not open for further replies.

Similar threads

S
  • Locked
Does a loose OAL not really affect .45 ACP accuracy?
Replies
3
Views
447
CZ9shooter
CZ9shooter
J
  • Locked
OAL question
Replies
4
Views
469
Mark whiz
M
S
  • Locked
OAL data for Dardas Bullets?
Replies
3
Views
834
rcmodel
R
C
  • Locked
Time to get out the bullet puller?
Replies
10
Views
608
chickenfried
C
Saluki91
  • Locked
.45ACP 185 gr XTP OAL Discrepancy
2
Replies
26
Views
923
mdi
mdi
Back
Top