OAL for lead and plated bullets !!!

chambered221

I can no longer get the bullet I used in my 9mm!!!

Looking around for a replacement I see no one list OAL for lead or plated bullets.
I have always used the manufactures listed OAL for my auto-loaders.
So the question is, How do you determine your OAL for your auto-loaders?

lesterg3

I think it's in Modern Reloading by R Lee. What are you going to use and I will check for you.

Bushmaster

In most cases if it will load into your magazine it will be correct AOL. another way is to match it with a like bullet in your load manual. Example: Rainier plated hollow points almost mirror Hornady's XTP.

SingleShotLover

Bushy's suggestion about matching to a similar bullet is probably the best idea. Depending on your chamber, depending on the fit to the magazine can cause you problems though. With semi-wadcutters, I can easily seat bullets that will fit into the magazine but will fail to chamber because they jam into the rifling on most of my .45s. Depending on your pistol, you can also pull the barrel and try hand seating your cartridges to see if they will chamber while still allowing proper headspace. This is easy with 1911 style pistols but shooters of other styles could maybe tell you if this is feasible with yours.

chambered221

Right now I’ll be working with Berry’s plated 147gr. RN.

I thought about trying to match it with another profile.
Not knowing the length of said bullet or where the ogive starts leaves a lot of room for error!!!

I’m thinking about locating where the ogive starts, adding .010 - .020 towards the base of the bullet and use that for a reference point to align with the case mouth to establish a OAL.
I already know that will fall into the 1.100-1.169 min/max OAL.
This bullet at 1.169 will work in both guns I have. I figure keeping them as long as possible should help with feeding.
I’ll then adjust my velocity to make the power factor I need. (this is a IDPA load)
Hopefully when all is said and done it will function reliably !!!

Bushmaster

Probably the most important part of the bullet determining powder charge and OAL is the bearing surface. If you can use your barrel for a gauge you can find the OAL. As long as you hear a very solid "clunk" when you drop the cartradge in you haven't reached the rifling...

chambered221

So your theory is to run them as long as physically possible despite the 1.169 SAAMI spec ???

wncchester · Member Joined: Apr 08, 2006 Posts: 160

Yes.

Understand that the length you quote is not a SAAMI figure, there are a LOT of bullets out there and SAMMI has no interest in establishing a specification for each one in every cartridge. Book OALs are just the lengths they used to develop the data, in their gun and with their components. It's not a law any more than the powder charges they list.

chambered221

wncchester wrote:

Understand that the length you quote is not a SAAMI figure,

Ohhh but it is !!!

wncchester wrote:

there are a LOT of bullets out there

And that’s why SAAMI list min/max data for the cartridge and not every bullet.

chambered221

Bushmaster wrote:

If you can use your barrel for a gauge you can find the OAL.

Thought about doing that !!!
But test rounds at 1.150 showed a significant pressure drop and was barely able to eject the fired case with a near max powder charge.

This is the one thing I don’t like about the 9MM, pressure rises and drops too sharply !!!

After that I stopped testing to rethink and ask others how they go about it.

I’m hoping to have some time tonight to pull the barrels out of the guns and do some measuring.

wncchester · Member Joined: Apr 08, 2006 Posts: 160

"Understand that the length you quote is not a SAAMI figure," --- "And that’s why SAAMI list min/max data for the cartridge and not every bullet."

Well. okay, sorta. But...I mean, minimum and maximum length is a range, not a specific point.

I just wanted to make the point to what I thought was a puzzled guy that the book OAL is not a law, so even if you deviate a several thousants from what you have been led to assume is a hard OAL your sights won't fall off nor will your magazine spring break. There is much more latitude to balancing a load-to-seating depth than a specific OAL +/- one thousanth. ??

But if you want to agonise over what SAMMI says instead of just finding an OAL that works, fine with me. Good luck.

chambered221

chambered221 wrote:

So your theory is to run them as long as physically possible despite the 1.169 SAAMI spec ???

When I posted the above it was nothing more than a question as to how Bushy went about determining his OAL.
It had nothing to do with me agonizing over SAAMI specs!!!

I started this thread to see how others determined a starting point when OAL data wasn’t available nothing more nothing less.

Pumpkinslinger

Chambered, I'm going to test some 9mm loads sometime, schedule permitting, where I took a load that had worked before and figured out how deep the bullet sat in the case. Then I took the new bullet (same weight, different profile) and seated it so I'd have the same size combustion chamber in the case. I haven't had a chance to shoot them yet but will be chronographing them when I do.

Bushmaster

Hey Chambered...I really don't worry about OAL for my pistols as far as whether they contact the rifling or not. I doubt that any of mine will. I did some experments using W-231 and bullet seating depth. If you set a bullet out too far you stand a chance of a bullet stuck in the barrel and failure to cycle the slide. If you set it in to short you risk a Ka-Boom. I set a .45 ACP out so far that it almost touched the rifling and only had the barest minimum amount of the bullet bearing surface in the case. Almost afraid it might fall out during cycling. My most interesting findings was that it really didn't make that much difference in accuracy whether the bullet was seated deep or shallow. I think you'll find the same thing. Remember...Revolvers have the longest trip from the case to the rifling of any handgun and still remain very accurate. Test platform was a Colt 1911 .45 ACP with a Wilson S/S barrel and bushing.

I usually seat my bullets longer (by a few thousands) then called for OAL. Example: 9mmX19 Lyman spec for 125 grain JHP is 1.075. I seat a 124 grain JHP at 1.100 +/- .002. .45ACP Lyman spec for 185 grain JHP is 1.175. I seat a 185 grain JHP at 1.190 +/- .002......

chambered221

Pumpkin, I’d be interested in seeing your results when you get to it !!!

Bushy, Thanks for all your info !!!

What little testing I’ve done in the past with (pistols) OAL also showed to be somewhat a waste of time !!!