How do you determine your OAL?

[johnniezombie]

With so many recipes (official and unofficial) it's difficult to determine OAL when loading plated bullets.

For example: How much of a difference is 1.224" vs 1.25" in a 45 ACP with 200 gr Plated RN with 5.5 gr of W231?

I haven't noticed a difference when I've adjusted OAL except the occasional jam.

I'm firing these in a Glock 21SF Gen3

[hermosabeach]

Is your question, how do I measure OAL with calipers?

Or since you have a min and a max allowed OAL to be within sammi spec, how did you pick the pal that you use when reloading?

With my experience, consistency give accuracy.

I was taught to load with a variety of lengths and when you find one that gives reliability and accuracy to measure out the OAL and log it into the book.

One of my springfields had an undersized ejection port.

It will eject all empty brass but it will not eject commercial ball ammo as the front of the bullet hits on the front of the ejection port. Well it will eject but you need to rack the slide with energy and it scratches the bullet and is hard on the extractor and ejector

So I can load a to the shorter side of the OAL and skip the problem.

And yes, I should have had the ejection port opened years ago.

[HighLander51]

.026" would be make a measureable difference in velocity across a chronograph but should not make any real difference in function. All recipes give a reference OAL because that is the load they checked. The maximum OAL is for the magazine, exceeding 1.275" could cause feeding problems. Going shorter of course increases pressure, but that doesn't mean you couldn't go below 1.190"
It depends on the bullet weight and powder being used. What is important is that you should not be measuring a .026" difference on rounds out of the same press setup. Variance should be less that .005"

[johnniezombie]

I know how to measure OAL with calipers. I don't know what you mean by sammi or pal.

I have been doing as you do, with test loads. I just wondered what the "professional or technical" method was for determining the proper OAL that coincides with your powder manufacturer, load, and bullet weight/type.

[HighLander51]

You kow how to read a caliper, then you are doing it right. Again, not terribly important as long as the loads are consitent.

[johnniezombie]

I'm loading with a Dillion RL 550B without any variations. I was doing manual adjustments between batches. ok so this effects the fps/pressure. Thanks for the help

[hermosabeach]

You have two types of calibers- wildcats and ones that conform to SAAMI.

Wild cats are rounds and calibers that are being built by someone and might someday become a mainstream caliber

SAAMI. - http://www.saami.org- sets the overall dimentions, size and specs for a round so that any ammo and firearm made within specs is safe to use. They set the pressure levels and cartridge dimensions.

[stilly]

I usually look at the MINIMUM, then maybe measure factory ammo, then see what will fit my gun, and stick closer to what will fit in my gun. CAUSE IF YOU CAN'T SHOOT IT WHY RELOAD IT? If you are using the BoLee, they give you MINIMUM OAL. Plated/Lead/Jacketed/Powdercoated makes no difference to me...

[mark501w]

I set to mag length check to see if it will eject, check for lands & groove marks ,build a dummy rd . Develope load from that point .

[ParaLarry]

I'm loading with a Dillion RL 550B without any variations. I was doing manual adjustments between batches. ok so this effects the fps/pressure. Thanks for the help

It is Absolutely Essential when changing seating depth on a 550B (like mine) or any progressive machine to put a case in EVERY station because the shellplate will flex and give you false readings at the seating die.
That's how you can get the variations down to .005.

[johnniezombie]

My next question is how the pressure is effected.

Shorter OAL = higher pressure/more fps or less?

[johnny1290]

For OAL I load a dummy round to max oal then check to see if it fits in the mags of all my guns, and will pass a bullet drop test into the barrel.

Well, I'd like to say I actually did that, but I checked it for 2 pistols and the others I added they work fine in too.

I don't benchrest a pistol or need to make a certain powerfactor for competition, or go for high velocity.

IMO, I think I'd rather change the powder or the size of the charge than adjusting the seating depth just to gain velocity.

I may be wrong, but that just seems a little too easy to KB for my comfort level.

I'm no expert or anything, JMO, I defer to those who are more knowledgeable.

Paralarry: Now *that* bit of info is good to know! I never would have thought of it, but now that you say it, it seems as plain as day. Thanks!

[HighLander51]

My next question is how the pressure is effected.

Shorter OAL = higher pressure/more fps or less?

yes, higher pressure yields higher velocities.

[HighLander51]

johnny1290

IMO, I think I'd rather change the powder or the size of the charge than adjusting the seating depth just to gain velocity.

I may be wrong, but that just seems a little too easy to KB for my comfort level.


Type of powder, charge weight and OAl all determine pressure and resultant velocity, for a given bullet weight, and the accuracy. However certain bullets load long and other styles load short because of the shape. True you could set a bullet deep enough to zoom up the pressure, but if you stay within the published recommendations it is not an issue. The object is of course to get the best accuracy with the least amount of powder.

[Bastard]

I load all my 45acp at 1.25x and as long as it feed it shoots, to be honest I have never had any jams or failures of any sort with my 45 loads... that said, I never did find a load that I liked using 231, sure it meters great but it goes downhill from there fast.