oal for .45--how critical?

akshooter · June 26, 2000, 07:51 PM

I've been having problems with my compact not closing to battery. Thought it was because of fouling due to Bullseye powder (I posted a question to this some time ago). Made more reloads, some with Bullseye and some with 231. Same-o with some rounds. My friend asked what I had my oal set at. ???? I used a caliper set to the diagram--give or take a hair. Well, it turns out the "hair" was crucial. Now I have all loads set at 1.275 per the Midway guide and they all seat in the chamber--which I now use to guage each load. The question--there really is one--is, how critical is oal? I've seen another post to this topic where some use 1.175. I guess I could set them less and give me an allowance. BTW, my friend was able to shoot all the ones my compact wouldn't shoot in his Colt Commander. Are tolerances that different?

zeke · June 26, 2000, 08:23 PM

Don't believe the Midway loadmaps were designed to show realistic COL, but to show how different powders worked pressure wise with same bullets. Use a loading manual that uses commonly available pistols and the bullet you are trying, to have a starting oal.

**Bud Helms** · June 26, 2000, 08:44 PM

They're different alright. I don't know how much chamber dimensions vary between mfrs, but if you have your bullets out to the max, you'll probably find a limit. Be careful to not set your bullets too far back in the case. Pressure could rise. Also, if you change bullet shape, the max OAL changes too.

I use 1.250-1.260. Methinks you are looking for fly doo-doo in the pepper. A caliper to measure OAL in a pistol?

Surely you jest. Modern, premium, jacketed bullets are pretty consistent, but the slightest debris in your bullet seater plug can throw off a meticulous measurement. While reloading a dropped bullet gets a flattened nose. Is it worth a panic? The OAL just changed!! No, not hardly. Just back 'em up a few thousandths and shoot. A .45 isn't a bench rest rifle. If the bullet's even 20 or 30 thousandths short of max OAL, it just won't make a difference.

It's a pistol. More to the point, it's a 1911 pattern. That is not a criticism.

I wonder if Roscoe Benson is around this thread. I'd be interested in his opinion on how critical OAL is in a .45 ACP.

[This message has been edited by sensop (edited June 26, 2000).]

alan · June 27, 2000, 05:30 PM

akshooter:

Re "does oal matter", if you don't mind feeding problems and things like the slide NOT going into battery, oal doesn't matter is the least. If you want your pistol, or rifle to work properly, it sure does, or it most certainly could.

If you were speaking of/to the 45 automatic, I have found the following oal to work quite well, with a 200 grain hard cast swc bullet (H & G 68, or similar), and the following powders: Unique, Red Dot, 231, Accurate #5. The oal is 1.260". A couple of thousands either way likely does not really matter, in most pistols, however if you get to long, you will find the slide not going into battery (closing comnpletely). The pistol won't fire. To short and you tend to get feeding problems (jams). That has been my experience.

Clark · July 12, 2000, 08:36 PM

There is a graph of pressure vs OAL in the pdf download http://www.ramshot.com/

Big Bunny · July 12, 2000, 09:41 PM

OAL is critical for chambering and magazines too in some hi-cap situations.

Try some experiments and check out commercial ammo with a ditital caliper.

You may be surprised at the variance indicated with various brands with no discernable effect on reliability or accuracy. A mild taper-crimp is good too...as I found on th FL a few weeks ago!

------------------
If we shooting sportspersons don't hang together... we will all hang separately !
Never knock another's different shooting interest or discipine...REMEMBER we are all but leaves on the same tree of freedom.

Airborne · July 14, 2000, 10:11 PM

Overall case length is also an important item to keep in mind with most autos as they headspace on the mouth. It would seem that most guns are headspaced deeper than max specified case length so that crud building up on the chamber lip will not adversely effect performance, but it can happen. I'm actually surprised that a round that wouldn't chamber because of OAL would still fit in the magazine of the gun properly. I know none of mine will. I typically load 1.260 OAL with 230 gr. FMJ .45's, but find no discernable difference in pressure by loading .100" deeper with the same near max loads. The .45 just has so much case volume that it doesn't seem to make much difference. The same cannot be said for the 9mm or the .40 Auto. .100" will make a BIG difference in near max loads with these high pressure cartriges. Oh, and by the way, the overall lengths listed in Midway's load books are MAX, although for some reason they negleted to point that out. Their loads are also VERY conservative IMO, although don't take my word for it....could be just me.

Happy loading,
SM

June 26, 2000, 07:51 PM	#1
akshooter Junior Member Join Date: January 23, 2000 Posts: 11	I've been having problems with my compact not closing to battery. Thought it was because of fouling due to Bullseye powder (I posted a question to this some time ago). Made more reloads, some with Bullseye and some with 231. Same-o with some rounds. My friend asked what I had my oal set at. ???? I used a caliper set to the diagram--give or take a hair. Well, it turns out the "hair" was crucial. Now I have all loads set at 1.275 per the Midway guide and they all seat in the chamber--which I now use to guage each load. The question--there really is one--is, how critical is oal? I've seen another post to this topic where some use 1.175. I guess I could set them less and give me an allowance. BTW, my friend was able to shoot all the ones my compact wouldn't shoot in his Colt Commander. Are tolerances that different?

June 26, 2000, 08:23 PM	#2
zeke Senior Member Join Date: November 17, 1999 Location: NW Wi Posts: 1,671	Don't believe the Midway loadmaps were designed to show realistic COL, but to show how different powders worked pressure wise with same bullets. Use a loading manual that uses commonly available pistols and the bullet you are trying, to have a starting oal.

June 26, 2000, 08:44 PM	#3
Bud Helms Senior Member Join Date: December 31, 1999 Location: Middle Georgia, USA Posts: 13,198	They're different alright. I don't know how much chamber dimensions vary between mfrs, but if you have your bullets out to the max, you'll probably find a limit. Be careful to not set your bullets too far back in the case. Pressure could rise. Also, if you change bullet shape, the max OAL changes too. I use 1.250-1.260. Methinks you are looking for fly doo-doo in the pepper. A caliper to measure OAL in a pistol? Surely you jest. Modern, premium, jacketed bullets are pretty consistent, but the slightest debris in your bullet seater plug can throw off a meticulous measurement. While reloading a dropped bullet gets a flattened nose. Is it worth a panic? The OAL just changed!! No, not hardly. Just back 'em up a few thousandths and shoot. A .45 isn't a bench rest rifle. If the bullet's even 20 or 30 thousandths short of max OAL, it just won't make a difference. It's a pistol. More to the point, it's a 1911 pattern. That is not a criticism. I wonder if Roscoe Benson is around this thread. I'd be interested in his opinion on how critical OAL is in a .45 ACP. [This message has been edited by sensop (edited June 26, 2000).]

June 27, 2000, 05:30 PM	#4
alan Senior Member Join Date: June 7, 1999 Posts: 3,847	akshooter: Re "does oal matter", if you don't mind feeding problems and things like the slide NOT going into battery, oal doesn't matter is the least. If you want your pistol, or rifle to work properly, it sure does, or it most certainly could. If you were speaking of/to the 45 automatic, I have found the following oal to work quite well, with a 200 grain hard cast swc bullet (H & G 68, or similar), and the following powders: Unique, Red Dot, 231, Accurate #5. The oal is 1.260". A couple of thousands either way likely does not really matter, in most pistols, however if you get to long, you will find the slide not going into battery (closing comnpletely). The pistol won't fire. To short and you tend to get feeding problems (jams). That has been my experience.

July 12, 2000, 08:36 PM	#5
Clark Senior Member Join Date: December 4, 1999 Location: WA, the ever blue state Posts: 4,678	There is a graph of pressure vs OAL in the pdf download http://www.ramshot.com/

July 12, 2000, 09:41 PM	#6
Big Bunny Senior Member Join Date: August 9, 1999 Location: New South Wales - Australia Posts: 605	OAL is critical for chambering and magazines too in some hi-cap situations. Try some experiments and check out commercial ammo with a ditital caliper. You may be surprised at the variance indicated with various brands with no discernable effect on reliability or accuracy. A mild taper-crimp is good too...as I found on th FL a few weeks ago! ------------------ If we shooting sportspersons don't hang together... we will all hang separately ! Never knock another's different shooting interest or discipine...REMEMBER we are all but leaves on the same tree of freedom.

July 14, 2000, 10:11 PM	#7
Airborne Senior Member Join Date: December 11, 1999 Posts: 229	Overall case length is also an important item to keep in mind with most autos as they headspace on the mouth. It would seem that most guns are headspaced deeper than max specified case length so that crud building up on the chamber lip will not adversely effect performance, but it can happen. I'm actually surprised that a round that wouldn't chamber because of OAL would still fit in the magazine of the gun properly. I know none of mine will. I typically load 1.260 OAL with 230 gr. FMJ .45's, but find no discernable difference in pressure by loading .100" deeper with the same near max loads. The .45 just has so much case volume that it doesn't seem to make much difference. The same cannot be said for the 9mm or the .40 Auto. .100" will make a BIG difference in near max loads with these high pressure cartriges. Oh, and by the way, the overall lengths listed in Midway's load books are MAX, although for some reason they negleted to point that out. Their loads are also VERY conservative IMO, although don't take my word for it....could be just me. Happy loading, SM