Officers Model 38 - Inconsistent Velocity Stats???

[TheTinMan]

Yesterday I shot identical loads through three revolvers and was surprised that my Officers Model 38 (6" barrel) was much less consistent statistically compared to two other pistols. One is a S&W Model 66-2 (.357 Mag chambers) with a 3" barrel. The other is a S&W 642 with a 1-7/8" (nominal) barrel.

	OM .38	66-2	642
Average	701	656	619
Spread	75	56	55
Std Deviation	24.9	16.9	18.5

Powder: Win 231 3.3 grains
Bullet: 148gr. Hornady HBWC
Primer: CCI Small Pistol #500

My accuracy was better with the S&W 66-2 than the Colt but that doesn't mean much since I wasn't shooting off a rest. However, the extreme spread and standard deviation are very close for the two S&Ws despite the difference in barrel length while the same stats for the Officers Model are almost 50% higher. Is it possible this indicates a timing issue or something else I should look for?

While I'm lost in the weeds, my Hornady manual shows a velocity of 750 fps for this load out of a 4" barrel. I expected a slightly higher velocity from my 6" barrel, not slower. I know that there are a lot of variables so am not sweating this much.

Thanks for your thoughts...

[Oyeboten]

One thing which occurs to me, is that there is very little Propellent/Powder in the Case at that Loading...and, I am not sure it would allow for consistent results just on that basis.

But...my re-Loading has been only Black Powder for .38 Special so far, and I have not dealt with any Smokeless.

You could try pointing the Colt 'up' and tapping it between each shot, and see if that makes any difference, since, if it does, you can then accept it is the behavior of the Powder in the Case which is making or contributing to the irregularities...even if the other two Revolvers were seemingly more consistent with their shorter Barrels, and, hence, one must assume, slightly shorter burn time for the rather scattered Powder.

Or, double check your Powder Measure with a Scale, to see if the charges thrown are consistent.

It is possible that in the Colt, with so light a loading, the Bullets are actually starting to slow down, too, before leaving the Barrel...and or this Loading if for the Colt may prefer a different Lube.

[Oyeboten]

How does WIN 231 compare to "Bullseye' for how much is used?

[TheTinMan]

How does WIN 231 compare to "Bullseye' for how much is used?

Hornady calls for 3.0 grains of Bullseye to get 750 fps (same as 3.3 grains of Win 231).

There really isn't much powder in the case, but the hollow base wadcutter does fill a fair amount of the case itself.

The bullets are Hornady, not mine, so changing the lube isn't an option.

I load powder in a batch on trays and always spot check at least 1 out of 10 to ensure consistency, more often when testing loads like this. My Hornady powder measure throws Win 231 fairly consistently - better than some other powders (like H-4831 for example). Besides, these rounds all were loaded at the same time.

Statistically - my strings were 10 or more shots each.

[smkummer]

My guess is that the longer barrel may be more prone to velocity variations with powder position. I would try muzzle up and slowly lower to the target while cocking (hopefully the barrel is at least horizontal or slightly up to the target) to see if the velocity variation lowers.

[TheTinMan]

On Sunday, I shot 35 rounds through my Officers Model 38 with 3.5 grains of Win231 under the Hornady HBWC. Standard deviation didn't move but extreme spread went up to 100. I was careful to raise the revolver, cock it, and carefully present to the target with each shot. Maybe the powder was still moving around in the case - there's a lot of extra room in there.

The good news is that I was able to get this target at 15 yards. I must admit that I stopped after 5 shots because it looked too good to spoil. This was my best target of the day. The Tyler T-Grip is taking a little time to get used to, but I like it a LOT.

[Oyeboten]

Nice Target!


Lets see some images of the OM itself, too..!

[TheTinMan]

Nice Target!


Lets see some images of the OM itself, too..!

Ask and you shall receive:
PICS

I have added Tyler T-Grips since those photos were taken, and they help me shoot a LOT better.

[WIL TERRY]

GENERALLY SPEAKING, if one gun gives wide extreme spreads and large SD'S in comparison to other guns being tested at the same time with the same loads it is caused by ignition problems, ie: IT ain't wailin' 'ell outta the primers enough !!! NOTE: primers are made to work correctly with the proper amount of impact being applied to them. They work even better if you really hit the dickens out of 'em with alacrity. As a matter of fact you can take standard pistol primers and turn 'em into MAG primers with heavy extra heavy firing pin impacts. YOU can also take MAG primers and turn 'em into standard primers with wimpy firing pin impacts.
This is the reason why acrossed the board the fastest guns by FPS produced in order are : RUGER, S&W, COLT,and bringing up the rear always, DAN WESSON.
AND to those who wonder, this is NOT by any guessing but by chronographing hundreds of various sixguns by all those makers by YEST for two different ammunition companies.

[Oyeboten]

Good mention there Wil Terry!