45 ACP OAL

[Dusty Miller]

Got to the range the other day with some 45 ACP reloads that I'd set the OAL to 1.275", max book. Well, they wouldn't fit into the magazines!! So, I brought'm home and reset them to 1.260", the same length as the Cor Bon cartridges I can't afford to shoot at the range! AND, they worked flawlessly in my WC CQB and Kimber CDP II. Previously the Kimber was jamming consistently with ammo I'd loaded but not to max book. So, I'm now convinced that 1.260" is the cat's meow, at least in my guns. YMMV

 

[Dusty Miller]

Got to the range the other day with some 45 ACP reloads that I'd set the OAL to 1.275", max book. Well, they wouldn't fit into the magazines!! So, I brought'm home and reset them to 1.260", the same length as the Cor Bon cartridges I can't afford to shoot at the range! AND, they worked flawlessly in my WC CQB and Kimber CDP II. Previously the Kimber was jamming consistently with ammo I'd loaded but not to max book. So, I'm now convinced that 1.260" is the cat's meow, at least in my guns. YMMV

 

[Sgt Preston]

Sgt Preston here. I have always set mine to 1.250-1.255 & also have perfect results. They feed 100% of the time in my 1911 & my PC945. I was told & have read more than once NEVER EXCEED 1.265 (when using 200 grain SWC's) to avoid feeding issues. I believe the 1.265 came on the papers with Wilson 1911 magazines a few years back. Sgt Preston USMC LLA

 

[Dusty Miller]

Originally posted by Sgt Preston:
Sgt Preston here. I have always set mine to 1.250-1.255 & also have perfect results. They feed 100% of the time in my 1911 & my PC945.

I'll load some like that next time around and see what happens. Thanks for the input.

 

[Skip Sackett]

Dusty,
There is one other aspect of shortening your OAL. When you do that you raise pressure in the case too. That isn't a problem if the load isn't at the top of the data. Shortening OAL on a maximum load can cause catastrophic problems.

Something else to consider about the pressure increase caused by a shortened OAL. It could be that your load is so weak that it doesn't operate the action reliably with the longer OAL.

Where do your cases land? Standing on the firing line looking downrange shoot several times. Notice where the brass goes. If it goes forward or stays even with you, you are on the bottom side of reliable cycling data.

Just another thought.


FWIW

 

[dennis40x]

To an extent OAL is determined by the weight and style of the bullet. The photo of the SWC of different weight and configuration illustrates this point.

 

[ChuckS1]

I always thought that the main thing to watch wasn't the OAL, but the amount of bullet inside the case, that in turn determines case volume and impacts pressure. Would be willing to bet that all four cartridges have the same case volume once those bullets are all seated. Dennis' picture shows that pretty well. OAL impacts whether it'll fit in your magazine and depending on the bullet design (like the 230 grain RN), if it will feed and chamber.

 

[dennis40x]

There is a difference between maximum OAL and what I would refer to as working/feeding/chambering OAL. I’ve seen variances of profile/contour in 230gr bullet weights that require differences in OAL in order to feed from a magazine or chamber properly. Bullet weight, bearing surface, and displaced case volume are contributing factors along with other variables.

 

[jjones33]

Here's another way to look at it. I ALWAYS load 10 or 12 rounds of any new bullet/powder and take them to the range first to chrono, check accuracy, check function and signs of pressure. Then I load or adjust and repeat if necessary. I usually make a couple or three different loads to take with me. Easy enough to disassemble a handful of rounds and start over.

As memtioned OAL should be set to the bullet manufacture's specs first time out.

 

[jibjab]

When I'm loading a bullet new to my semi-autos I assemble a few dummy rounds. First I find the max COAL for my barrel chamber, http://www.thehighroad.org/attachment.php?attachmentid=91243&d=1232308690
and then I find a COAL that manually cycles in the action. This gives me a pretty good start for finding the COAL that works in that pistol.
I forgot to mention, I will lock the slide back with the dummies in the mag and hit the slide release, this will help determine if there will be a bullet set back issue with that COAL.

 

[Skip Sackett]

Originally posted by dennis40x:
There is a difference between maximum OAL and what I would refer to as working/feeding/chambering OAL. I’ve seen variances of profile/contour in 230gr bullet weights that require differences in OAL in order to feed from a magazine or chamber properly. Bullet weight, bearing surface, and displaced case volume are contributing factors along with other variables.

Couldn't have said that better myself.

 

[Dusty Miller]

Originally posted by smith crazy

usty,
There is one other aspect of shortening your OAL. When you do that you raise pressure in the case too. That isn't a problem if the load isn't at the top of the data. Shortening OAL on a maximum load can cause catastrophic problems.

Something else to consider about the pressure increase caused by a shortened OAL. It could be that your load is so weak that it doesn't operate the action reliably with the longer OAL.

Where do your cases land? Standing on the firing line looking downrange shoot several times. Notice where the brass goes. If it goes forward or stays even with you, you are on the bottom side of reliable cycling data. FWIW

Thank you, good information. Yeah, I'll definitely watch for any sign of excessive pressure. Right now my cases are falling MOSTLY behind me with just a few off to my right and none out in front. I think I'm OK there.