OAL Determination

[Blaine]

I've mentioned before that I only "dabble" in reloading. When reloading for rifles, I have been loosely crimping the bullet, and and chambering it. That's my OAL. I don't do this on pistol calibre rifles, and if I have more than one rifle in that calibre, I don't mix brass.
What say the experts?

[AJMD429]

That seems sensible.

I've seen guys who use "recommended OAL" in their reloading, yet are using completely different bullets than specified, with different ogives. The "length" that matters from a pressure standpoint is that 'length' from cartridge base to the part of the bullet that is/will engage in the rifling at the throat, not simply the length from cartridge base to bullet-tip.....you could embed a 2" sewing needle into the tip of a bullet, by drilling a hole into the bullet that removed the identical weight in grains of lead from the bullet.....that would have a huge "OAL", but would not matter in terms of pressure.

The other factor is bullet stability, and for that, the only 'OAL' that matters is the length of the projectile, versus the RPM's which are determined by rifling twist rate and velocity.

[crs]

No Comment.

[Chuck 100 yd]

I only have five or six rifles that I load to an overall length that gives best accuracy. They are all bolt guns with match quality barrels.
I load all my .45 colt CAST BULLET ammo to a length that runs in my Uberti 73 and it does great in revolvers and other levers. Everything else just gets loaded to suggested o.a.l. listed in the manuals.

[Griff]

The only guns that give me problems with OAL are the .223 ARs and 45 Colt toggle-link Ubertis. The only rifle I load to the lands are my Rem 700s.

However, none are "loosely" crimped. I don't crimp my 7mm RemMag, but rely on a very tight neck tension. I use a roll crimp on all my other loads, except those that need a taper crimp. I still like a tight neck tension.

[AJMD429]

The only guns that give me problems with OAL are the .223 ARs and 45 Colt toggle-link Ubertis. The only rifle I load to the lands are my Rem 700s.

However, none are "loosely" crimped. I don't crimp my 7mm RemMag, but rely on a very tight neck tension. I use a roll crimp on all my other loads, except those that need a taper crimp. I still like a tight neck tension.

I think he meant he just does a 'loose crimp' for the purpose of then chambering a round, and using that for maximum OAL....crimping actual loaded rounds at that or slightly shorter.

[sore shoulder]

I use the recommended oal for semi autos, esp if i have several guns chambered for the same round. If the round is dedicated for a single gun such as a bolt action, I do the just off the lands trick. Almost everything I load gets a Lee FC.

[Blaine]

No Comment.

Heck....Don't hold back. I might learn something.

[Pete44ru]

.

The only comment that I can make is that determining the OAL via loosely-seating the bullet & chambering the (dummy) round might result in a cartridge that, although satisfying as a single-shot rifle cartridge, may well be too long to reliably feed reliably through/from the rifle's magazine (if a repeater is desired).

I always make up the dummy, then manually cycle it through the action, caseful that the loose bullet doesn't stick in the barrel rifling's leade when the dummy is withdrawn.


.

[Tycer]

If I'm using jacketed, I set it in another 0.002" deeper. Cast can engrave for me. I only do it for accuracy loads and use published OAL for hunting unless I have a rifle that must have the longer length to shoot well AND that can always cycle that round. That was one rifle and I no longer own it.

[marlinman93]

When I get a new gun I play with OAL to see what works best. Not only to ensure proper cycling through an action, but also to see what bullet depth seems to give the best accuracy. Sometimes touching the rifling doesn't produce the most accurate load, and a particular gun might shoot better with a deeper seated bullet.

[mikld]

When I load my rifle ammo, I start with the bullet manufacturer's recommended OAL for the particular bullet (sometimes a cannalure or crimp groove lines up, but that isn't used to determine OAL). I only crimp for my semi-auto rifles and then just lightly. I use book data to start and for my bolt gun, then later I use one of Hornady's tools to try to find optimum seating depth/OAL for that particular bullet. I don't mix brass, rifle to rifle, but I keep batches separate for number of times fired, especially for my Garand...

[crs]

Blaine - you said = "Don't hold back" so here goes:

I was not sure if this was another of your great jokes/puns or if you were serious!

If a joke, it amused me.

If you were serious, there were so many (hundreds, maybe thousands) of things to know or say that I just gave up.

If it works for you, it must be OK.

[Blaine]

Blaine - you said = "Don't hold back" so here goes:

I was not sure if this was another of your great jokes/puns or if you were serious!

If a joke, it amused me.

If you were serious, there were so many (hundreds, maybe thousands) of things to know or say that I just gave up.

If it works for you, it must be OK.

I'm still learning. I had three different 45-70 levers that all needed a different OAL to chamber the round properly. If I had a Ruger #1 in 45-70, that would have been a fourth.
Pursuant to OAL, enumerate, say, fifty "things"......
Honestly, I thought it a bit "strange" to respond the way you did.

[Grizz]

could someone address the effects of decreasing OAL on cartridge pressures ?

thanks

[Griff]

could someone address the effects of decreasing OAL on cartridge pressures ?

thanks

If the projectile is seated deeper in the case, the same powder charge will increase pressure.

[Griff]

The only guns that give me problems with OAL are the .223 ARs and 45 Colt toggle-link Ubertis. The only rifle I load to the lands are my Rem 700s.

However, none are "loosely" crimped. I don't crimp my 7mm RemMag, but rely on a very tight neck tension. I use a roll crimp on all my other loads, except those that need a taper crimp. I still like a tight neck tension.

I think he meant he just does a 'loose crimp' for the purpose of then chambering a round, and using that for maximum OAL....crimping actual loaded rounds at that or slightly shorter.

Ah! Yeah, I've done that.

[Blaine]

The only guns that give me problems with OAL are the .223 ARs and 45 Colt toggle-link Ubertis. The only rifle I load to the lands are my Rem 700s.

However, none are "loosely" crimped. I don't crimp my 7mm RemMag, but rely on a very tight neck tension. I use a roll crimp on all my other loads, except those that need a taper crimp. I still like a tight neck tension.

I think he meant he just does a 'loose crimp' for the purpose of then chambering a round, and using that for maximum OAL....crimping actual loaded rounds at that or slightly shorter.

Ah! Yeah, I've done that.

Just one of thousands of ways at least one Lever Gunner knows about.

[Grizz]

could someone address the effects of decreasing OAL on cartridge pressures ?

thanks

If the projectile is seated deeper in the case, the same powder charge will increase pressure.

percent changes?

critical no-go depths?

least and most sensitive powders, or fastest and slowest rates of pressure increase?

you know, knowledge based information . . .

[Rusty]

Driving 50-60 hours a week one of the things I've found to help me retain what little sanity I have left is podcasts online. There is a reloading podcast put out by the Firearms Radio Network. The panel members there have different interests and levels of experience.
There is also a corresponding Facebook page that listeners and members participate in. A lot of questions brought up on the Facebook page are addressed on the podcast.

[JFE]

Assuming we are talking leverguns, the first point to note is that most rifle caliber chambers in leverguns have little to no throat. So the projectile's size and shape ahead of the crimp groove will have a bearing on the OAL. Quite a few FN levergun projectiles are two diameter designs to account for this lack of throat. One notable exception in rifle chamber throats is the 375 Win, which has quite a large throat.

In contrast, most pistol cal leverguns have quite long throats. My 44 mag has a throat length of around 0.22". In my levergun i would never be able to load a bullet that can reach the lands and still cycle through the action.

There is also a restriction on the OAL that will feed and function in a levergun.

Taking your example of the 45/70 in leverguns, a lot of the levergun jacketed bullet offerings these days are designed for optimal fit in a 1895 Marlin. The Marlin is designed to function with an OAL of 2.55-2.57". The 1886 based actions can utilise a much longer LOA but the short throat restrict the LOA that can be used. You can either have the throat lengthened or utilise cast bullets that are a two diameter design. The downside with lengthening the throat is the possibility of spoiling accuracy with shorter bullets, particularly cast bullets.

In my Marlin I am restricted to an OAL of around 2.55" but in my Browning 1886 I can utilise an OAL of around 2.88" or so, ie with suitable bullets you can effectively load an 1886 to the same length as a 45/90. I have a few cast bullet moulds where I am able to optimise my use of the 1886 with the stock throat. A Ruger No.1 has no OAL limit, but the chamber will still have the short throating. Just like the example of the 1886, you can use two diameter (and ideally bore riding) designs to increase performance and enhance accuracy.

[Griff]

could someone address the effects of decreasing OAL on cartridge pressures ?
thanks

If the projectile is seated deeper in the case, the same powder charge will increase pressure.

percent changes?
critical no-go depths?
least and most sensitive powders, or fastest and slowest rates of pressure increase?
you know, knowledge based information . . .

Since answers to your questions are not of a linear nature, almost any such discussion is depend upon the specific cartridge, bullet, powder, case, primer combination and weapon being used or contemplated.

It's why my recommendations are rather conservative... what might be a safe combo in my gun, might not be in someone else's. It's why when I work up a new load, I tend to take all the available published information I can gather, and if I'm working for a hunting or target type load, I'll start with the info on as near as possible the same bullet weight, shape as I have/buying/contemplating and start with loads listed near the median of that data. I will play with OALs to see what will feed thru my action and seat in the chamber with the minimum of fuss (like none), compare that the recommended OAL, and determine if my starting load needs to be dropped or I can proceed with experimenting. If my data source happens to have the exact same bullet I'm going to experiment with... I ain't experimenting much... just determining what then works in my rifle. However, if I don't have access to data for "my" bullet, I feel it mandatory that I compare seating depths, or, I might start with data for a bullet that's a few grains heavier.

In the case of levers and autoloaders, generally, I've found that there's a fairly narrow band of what OAL that will cycle thru the action. (I've read that somewhere also... and in ignoring that I've had some nasty jammed rifles)! It's why now... I tend to not experiment as much!

The things I read when I first started reloading 42 years ago, seem to have held true during all this time... things like:

• • the maximum loading seldom yields the most accurate load
  • touching the lands with the bullet, "CAN" result in insanely accurate loads
  • never have two types of powders on the bench at one time
  • when changing any single component, rework the load anew

Among many others.

For this reason, when I think about loading a particular bullet deeper in the case, my first thought is, "... do I REALLY want to rework this entire load?"

I.e.: My 45 Colt loads for my various leverguns. I initially worked up this load for an 1873 Uberti Sporting Rifle with 24-¼" barrel. At the time I had been using a 185gr. WFN bullet in my SAAs. I used the same load in the rifle... keyholed @ 25 yards. While this may be acceptable accuracy for CAS matches now... in late 1986 it most assuredly wasn't! Since I knew I wanted to shoot BP, pressures weren't of any concern. BUT, AOL was! That carrier mortise in the 1873 ONLY allows a certain max length cartridge... and the ramp on the front of the carrier will only push the next cartridge back in the mag tube if the one on the carrier is "so" long. All well and good, except... even the 200 grain bullets I had didn't carry enough lube to avoid hard crusty fouling about 4" from the muzzle. Hey, in 1986 having a custom mold made never entered my mind... I'd never even hear of it being done. But... RCBS had this nifty mold, the 45-225-CAS listed in the catalog. Nice big lube groove, 225 grain as thrown with Lyman #2, (even lighter with my 6:1 WW:Linotype), truncated flat nose... PERFECT for a levergun!

However, I knew that for side & team matches I would want some smokeless loads. (Not that I've always used 'em)! I started off with a median load for a 230 grain RN in the book. I worked that load up in search of accuracy at longer ranges (out to 200 yards), and down in search of lighter recoil, or in a nod to speed, faster recovery time. For ease of loading, I kept my loads in the crimp groove. (I had my Dillon 550B by this time). I found several loads that worked for both long range and speed work using a couple of different smokeless powders. As long as wind wasn't a factor, the same slow speed CAS load worked out to 200 yards with accuracy off the bench that proved competitive for me. All's good, no?

In 2008, I bought a Uberti Henry in 45 Colt. Luckily I found that the same OAL worked, and accuracy was even better in this rifle. Nice, huh?

In 2014, I bought another Uberti 1873, this one with an 18-½" barrel. Took it out and fired the same rounds over my then new chronograph. WOOHOO! Excellent results! Only I made a grave tactical error. I didn't test it with ALL my usual ammo... especially thru the magazine. I used it in WB matches for over a year, using a 200grain RFN loaded in the crimp groove. I somehow ran out of this ammo, picked up the wrong can... whatever, at a recent CAS match, I loaded it up with my 225TC ammo and loaded up at the table... took it my shotgun and pistols up to the firing line... set 'em up to shoot the stage. I don't remember which gun was first... all I remember is that the first round wouldn't feed up the carrier mortise. It's .002" shorter than either the original 1873 or the Henry!

My point? While shortening up the OAL on this ammo by .003" is not likely to increase pressure up into the dangerous level, it did increase my velocity a few FPS.

[1886 45-90]

Blaine - you said = "Don't hold back" so here goes:

I was not sure if this was another of your great jokes/puns or if you were serious!

If a joke, it amused me.

If you were serious, there were so many (hundreds, maybe thousands) of things to know or say that I just gave up.

If it works for you, it must be OK.

I'm still learning. I had three different 45-70 levers that all needed a different OAL to chamber the round properly. If I had a Ruger #1 in 45-70, that would have been a fourth.
Pursuant to OAL, enumerate, say, fifty "things"......
Honestly, I thought it a bit "strange" to respond the way you did.

OK, here's a big one: OAL has a huge effect on pressure. If you change the OAL by .1", you could easily change the pressure by several thousand PSI. This can work against you both directions - jamming the bullet out into the lands increases pressure because the shot is hard to get started since the bullet can't get a run at the lands and shortening the round increases pressure because it reduces effective case capacity.

Reloading data has an OAL associated with it and is for a very specific bullet. If you can't find the OAL, don't use the data. If you can find it, but it doesn't fit in your gun, don't use the data. If you have to change the OAL, you have to do a new load work-up. That ideally involves pressure testing equipment, especially on leverguns that don't have good pressure signs.

Bullets also often have a limited range of OALs they work with to ensure proper crimp. Sometimes you can wander outside this range if you have a Lee factory crimp die. Sometimes not. Depends on the bullet design.

[Blaine]

If you have to change the OAL, you have to do a new load work-up. That ideally involves pressure testing equipment, especially on leverguns that don't have good pressure signs.

That's a given. And, yes, you are absolutely correct. Thanks.