Interesting Discrepancy - .45 Colt loads

[GasMan]

I loaded up a batch of .45 Colt loads, I am looking for just about 900 fps with Oregon Trail 250-gr LRNFPs. The load I was trying today is 8.0 gr of Universal, which according to John Taffin and several other sources is supposed to be about the same as the old full power BP loads. The cases are new Jagemann's, nice stuff, OAL 1.580" per the Oregon Trail manual. The charges were weighed and trickled. All crimped the same.

Funny thing is, the chrono data. I will say I was a little disappointed with the ES and SD which were about upper 40s and low teens, respectively. I was disappointed to see that in rounds that I assembled so carefully, I have done much better with Unique in .45 Colt. Those values are more in line with what I get in my mixed brass 9mm loads I load on my Dillon 550B thousands at a time.

Anyway, first 12 rds were fired through my 5.5" New Vaquero with an average of 873. Ok, not quite what I was looking for, but they were pretty good loads.

Then I chrono'ed the same rounds in my 5.5" Blackhawk, and the result surprised me, the average for 12 rounds was 920 fps, hmmmm. Close to what I wanted, but not quite, I know, well within the capabilities of the gun. So I have 27 fps below target in one gun, and 20 fps OVER target in the other gun, with the same length barrel. Interesting.

The 8.0 of Universal seems like an ok load, fun to shoot, I like it, but can someone explain to me what in the Wide Wide World of Sports is a going on with the velocities?

Any thoughts/observations welcomed!

ETA - ES and SD values were a little off in orig. post

 

[Sagebrush Burns]

I have chronoed the same 45 Colt load in six different SAAs of the same (7 1/2") barrel length and seen nearly 100 fps variation among the guns. Chamber and barrel dimensions differ from gun to gun. That's life...

 

[GasMan]

Thanks, that's interesting, I did not expect the velocities to be identical but also did not expect 50 fps difference either. I guess I have never had occasion to chrono two guns side by side like that. Always something to learn.

 

[Johnnu2]

I can't answer your question, but I can tell you that I've never strayed from Unique in my .45Colt loads.
My only criteria has always been whether or not I could hit smaller targets. I tested with a chrono way back in the OLD DAYS (1970's) with a friend who had one (probably a hand-crank for power .
Anyway, the interesting thing (to me) was that for each one-grain of Unique that we added, we got exactly 100 fps on his chrono (using a jacketed 250 gr HP.... I think it may have been a Hornady bullet). We started at 7 gr (700 fps) and continued up from there. I won't tell you how high we went because we were young and stupid, but I will tell you that we were shooting my OM Ruger Blackhawk (which I still have), using range-pick-up brass. Based upon totally unscientific 'data' Unique seemed to be consistent back then . It was a fun experiment and probably bears no value today other than a story from an old guy.
IMHO,
J.

 

[Rclark]

In my tests 8.0g Universal under 250g RNFP (BHN 12) had an ES of 44 of 13 shots. Velocity was 894fps. Note that using a magnum primer doubled the ES to 88. Likes the standard primer (CCI-300). Oh, this was better than my Unique tests where the ES was in the 50s.

Then I chrono'ed the same rounds...

BTW, that is why I have one 'test' gun (in the .45 Colt it is a large frame BH 5 1/2") for my load testing for each cartridge. That way, I am comparing apples to apples velocity wise. Also as a side note, the load may be accurate in this gun, but not so much in another. So chronographing really just tells you the average velocity and how consistent the load is. Consistency will never hurt accuracy. And I like to know what velocity the load should be giving.

 

[GasMan]

Thanks guys. I am going to shoot some more Universal but I think might as well go back to Unique also. I was trying Universal because it is supposed to meter better than Unique, but frankly I didn't see much of a difference and I would need to trickle the loads anyway, I get a little bit tighter numbers with the Unique.

 

[Rclark]

Metering depends on the powder drop device. Universal seems a bit more consistent in mine. BTW, I will never reload where I have to 'trickle' to make up general purpose loads. Nope notta . If it doesn't meter well enough, I won't use the powder. Unique meters well enough where the amount is 6g or more. Below that it stinks. So I use Unique in my .44s. Green Dot is my current .45 Colt powder.

 

[gunzo]

Same barrel lengths, even with nearly identical chamber & bore dimensions that show a good bit of velocity differences will likely have different cylinder gaps.

A wide cyl. gap can cause as much velocity loss as most variables.

 

[contender]

As you can see from others experiences,, there are many variables that can create the differences you have seen. Another variable,, is the actual bore diameter,, and how well the "seal" is when a bullet travels through it. Or, a rougher bore vs a slicker bore. Heck, even if you use different lot numbers of primers or powders, that can cause variations.

This is why a person needs to build a load,, for each gun, and use that when chasing the absolute accuracy they can possibly get. But,, if general use in several guns is desired,, then finding a good "average" load will suffice too!

There is a post over on the CB forum,, about a guy chasing the ultimate load in a gun to achieve that magical one hole group accuracy. I knew before I even opened the post,, that such a load is impossible,, as the one variable in accuracy is the shooter. And yep,, when I read his post,, he actually admitted that HE was the problem,, and needed to work more on his shooting ability.

There are several things, (variables) in shooting to where it's HARD to get exact, darn near perfect consistent ammo each & every round. Benchrest shooters chase that a lot.

 

[GasMan]

Thanks, this is all good stuff, I just never had more than one gun of the same type, with the same barrels, to chrono loads in, but it makes sense. I am having fun with it, don't know why I waited so long to get into the single action .45 Colts.

 

[Rclark]

...don't know why I waited so long to get into the single action .45 Colts.

With you there.... I didn't get into .45 Colt until I was in my early 40s.... Before that it was .357s and .44 Magnums.... Can't go back, so glad I found the cartridge when I did. Now I won't be without my .45s! Go figure.