seating max.o.a.l vs Min o.a.l

[Jc85]

when working up new loads I use starting grains and reduce oal from max to somewhere above the min.
now the question im asking is what do you guys usually seat to? more twords max or around min? Going for accuracy..

Thanks guys
Jc

 

[Alk8944]

Since this is the S&W Forum I am going to assume you are asking about a handgun, is this correct?

For a revolver, if you are loading a bullet with a cannellure (crimp groove) seat to crimp in the cannellure and forget about cartridge lenght as really you can't do anything about it. If you are looking at a bullet manufacturers manual all the COL dimension is their bullet, loaded in a normal length case, will give the noted OAL. It doesn't mean there is something "correct" or magic about that length.

For semi-automatic pistols the COL does mean something. Maximum should fit in the magazine of the average pistol chambered for the cartridge. Minimum could be for function, or safety. A bullet seated to less than minimum OAL, with a maximum or near maximum pressure charge, could result in grossly exaggrated and possibly dangerous pressure when the cartridge is fired.

Just remember COL length is usually merely an indication of a practical range of length, or a result. It is not a specification, usually. If shown with a cartridge drawing as a maximum, then all it means is that SAAMI standards for commercial ammunition in that caliber should not exceed that length or they may not fit the magazine of, or the cylinder, of standard, commercial, firearms chambered for that cartridge.

 

[Rule3]

I use the OAL that will fit in the barrel of my gun (semi autos)
By taking the barrel out and testing a inert round it should drop in and fit flush and drop out. Especially when using lead bullets, several guns such as CZ and Brownings require the bullet to be seated much shorter than indicated in the manual due to the short leade (chamber). Jacketed bullets which have a sharper point are not a problem. Generally though the data in the manuals or powder companies info, the MIN OAL should not be any shorter as that is where they were tested with the indicated powder charge and still safe.
Look at the Hodgdons powder data for 230 gr bullets in 45 ACP. Every OAL is 1.20 there is no min or max OAL

Cartridge Loads - Hodgdon Reloading Data Center - data.hodgdon.com
For revolvers, what Alk8944 said.

 

[kingranch]

They’re two major components to consider and hopefully champion in order to shoot straight: repeatability/discipline (that would be the shooter) and consistency (that would be the gun/ammo combination)…don’t worry if the bullet-holes are not even close to the 10X. Experiment with different loads and concentrate on one particular firearm/caliber at the time. Anything after that it’s just a sight adjustment. As far as rolling my own…I like to keep it at set max OAL for automatic pistol. Revolver OAL is set by bullet design like the poster above said.

 

[Jc85]

yes for autoloader.
so your saying that OAL really does not affect accuracy. The main purpose is to have it so it feeds nicely, and generally speaking having the same load of bullet/cartridge/charge would offer no noticeable affects on accuracy with different OAL. yes I understand that pressure is increased wich could inturn increase velocity that might be more accurate. but increased pressure isnt really what im going for, not to mention being potentially hazardous. Just a general question about what most of you seat to and is there anything beneficial to seating near min.

thank you for the answers guys.
JC

 

[Notoast]

I think OAL can affect accuracy in handgun ammo. If your brass are all the same length and your powder charges are the same, then different OAL will result in different pressures because the volume behind the bullet will be different.

 

[Rule3]

yes for autoloader.
so your saying that OAL really does not affect accuracy. The main purpose is to have it so it feeds nicely, and generally speaking having the same load of bullet/cartridge/charge would offer no noticeable affects on accuracy with different OAL. yes I understand that pressure is increased wich could inturn increase velocity that might be more accurate. but increased pressure isnt really what im going for, not to mention being potentially hazardous. Just a general question about what most of you seat to and is there anything beneficial to seating near min.

thank you for the answers guys.
JC

No, everything affects accuracy. Changing OAL will also. Lots of rifle shooters want the bullet just off the rifling.

With handguns that is not always a good idea. Too long and they will not feed. to short and and you increase pressure and bad things happen. Go with what the reload data states. Check to see if it chambers properly, if not you may need slight adjustment.

I used the data for a Hornady XTP 45 ACP OAL. Like a dummy I did not check the one handgun I was planing on shooting. They would not feed at all and really jammed up the gun. Tried it in some other 45's and it worked fine. So I had to shorten the OAL for it to work, but I had loaded at min powder charge so did not worry about shortening them.

That's why you start low and work up. Only load a few 10 or so in case you need to adjust. Breaking apart 100 rounds is not fun.

 

[Maximumbob54]

I also worry about OAL when reloading certain brass. Hornady is using some odd length brass for their .45 Colt ammo and it all comes up short. If I seat to the same depth to give the same cartridge OAL then the bullet isn’t seated in deep enough. I guess it is a known issue but it was new to me a few weeks ago. Another plus for the super easy Lee dies seating depth adjustment design.

 

[Rule3]

I also worry about OAL when reloading certain brass. Hornady is using some odd length brass for their .45 Colt ammo and it all comes up short. If I seat to the same depth to give the same cartridge OAL then the bullet isn’t seated in deep enough. I guess it is a known issue but it was new to me a few weeks ago. Another plus for the super easy Lee dies seating depth adjustment design.

On a revolver with lead bullets, just go to the cannelure. Some manuals have trim to length which is shorter than the regular or standard length. On handguns I have no idea why they do that?

The max case length of 45 Colt is 1.285. They trim theirs to 1.275.

I guess they do that to insure(sp?) all cases are exactly the same.

I have their new manual and they trim even more if using their new FTX bullets

 

[Aticus]

I've a bit of experience at hand loading but would some one tell me where you find data which shows a min or max OAL for ammo?

I've looked at Hodgdon's data section and all I see is one measurement for OAL. I like to increase my knowledge when I can.

Pecos

 

[Rule3]

Most any reloading manual will show you the max Saami max OAL

The manuals will also show the trimmed to length and the loaded OAL for the test load.

The Hodgdons online data only shows the trim length and the loaded oal.

A manual will show all dimensions of the brass.

 

[Jc85]

lol I sometimes wish in the world of reloading there were definitive answers. I enjoy experimenting and working on loads tho.

 

[OKFC05]

I've a bit of experience at hand loading but would some one tell me where you find data which shows a min or max OAL for ammo?
Pecos

SAAMI cartridge specs give a spec max OAL.
Cartridge Specifications

However, chambers that are over SAAMI spec length can accomodate a longer OAL cartridge, as many USPSA STI shooters can confirm. An "STI loaded .40" will not chamber in my Brn HP.

The minimum length is harder to pin down, as it depends on the relationship of the action, loading, bullet, and powder. For example, a revolver WC can be loaded flush with the case mouth using a light charge of fast powder with no problem, while that would be a major feeding problem for most autoloaders.

If you are loading a cartridge near max, it is dangerous to reduce the OAL below what that specific loads specifies, due to pressure increase by changing the expansion ratio.

And about the time you have it all figured out, along comes a bullet with a new fat ogive shape that sticks in the rifling using the same OAL for your old bullet.

 

[Rule3]

lol I sometimes wish in the world of reloading there were definitive answers. I enjoy experimenting and working on loads tho.

There are many definitive answers.

Just when you think you have a grasp on it all, something "new" comes along.

I think the biggest variable is that there are so many bullets, projectiles.

If someone bought only Speer or Hornady bullets for example and had their respective manual. loaded exactly as it states that the manual did, it would be pretty simple.

Due to all the different bullets, primers, powders anything can change. Even using thicker military brass as compared to commercial brass changes the inside capacity.

It a definitive learning hobby and fun.

 

[Aticus]

Uh fellas, I thought the OP was speaking of OAL. To me and the manuals I use that is CARTRIDGE over all length. I know there is a min and max CASE length, along with a trim to length. I was just trying to find out where there is a list for OAL min and max. And before anyone brings it back up I know there are SAAMI specs for all cartridges including max OAL. My manuals show an OAL for whatever bullet and load they tested.

I hope that clears up my question and I'd still like to know where these min and max dimensions are.

Pecos

 

[Notoast]

@Pecos, As you note, the "official" max cartridge OAL is the SAAMI spec. The max "practical" length in a revolver is one where the bullet does not protrude from the cylinder where it would contact the forcing cone. In a pistol the max practical length would be one where the bullet is almost touching the rifling in the barrel (as long as this length will cycle okay). These "max" specs are dependent on the firearm as much as the cartridge and may or may not be safe depending on the length of the bullet! I know of no formal min OAL dimension since there are so many combinations of bullet and powder charge. For example, you can load some 38 wadcutters flush with the mouth of the brass, but you wouldn't do that with a round nosed bullet of the same weight using the same brass.

 

[Rule3]

Uh fellas, I thought the OP was speaking of OAL. To me and the manuals I use that is CARTRIDGE over all length. I know there is a min and max CASE length, along with a trim to length. I was just trying to find out where there is a list for OAL min and max. And before anyone brings it back up I know there are SAAMI specs for all cartridges including max OAL. My manuals show an OAL for whatever bullet and load they tested.

I hope that clears up my question and I'd still like to know where these min and max dimensions are.

Pecos

The Lee manual which lists a compilation of load data from other sources lists a Minimum length to not go shorter than for the loads.