Home Forums Hunting & Shooting Ask The Gunwriters Losing velocity, it's not the chrono...any ideas???

With modern 'smokeless' powder AND lot to lot variation...

I don't trust 'volume' measurements.

Yep, it works with Black Powder, etc.

YMMV


Jerry

catorres1 -

Yes, I call it "shooting interruptus"..

Thanks for the reply.

Jerry

Wore out, wearing out barrels slow a lot. Really a lot.

Why don't you trust 'volume'? Try it with a micrometer measure and two different powder lots and see which one is more consistent in velocity with your original load. I think you'll be surprised.

Because in the past I've had 'several' less than desirable results with KNOWN loads in modern powder SIMPLY by getting a new lot of powder.

1 example - I have had TWO blown primers at DIFF times and DIFF lots of a popular powder--now OFF PRODUCTION line.

2nd example - I still have most of a pound of a diff powder altogether with LOT # recorded. It gave OVER pressure loads AND 100+ fps. I can use it but MUST reduce the charge by @ 3 grs. (volume IS diff)

3rd example - Others who participate here had BLOWN primers by changing lots of ANOTHER diff powder. It too has been taken off production.

TOO many experienced problems personally PLUS others reporting the same problems with diff powders.

Go right ahead, it's not my fingers, nose, or eyes.

Jerry

Yes indeed. As the bore wears it increases inside dia. and less pressure and less velocity are the results.

In this case, I don't remember if/not the OP told us how much this barrel has been shot.

Jerry

Guys,

The barrel is brand new. 50 rounds through it total so far.

Edit: Sorry, that was for the 300. For the 260, probably 100 rounds through it. Maybe 150. Still, basically new.

Don't you just hate it when you have to "pull out before you get thru "


Jerry

In our previous discussions per Losing Vel and Chronographs:

I had to REplace my O 33 skyscreen IIs. I've had the IIIs a while but was not satisfied with them mounted on the board that I've been using.
Pic 1 is of Skyscreen II


That has worked virtually flawlessly since 1981 but a couple of yrs ago I was getting funky numbers and inconsistency. I called Oehler and they sold me the Skyscreen IIIs that work with the Model 33.

In the past week or so I got a 'larger' board to mount the IIIs on that gives much better protection. This board is a rough cut FULL 2"X6" and the IIIs sit in and on better.

Also the screens are mounted LEVEL with each other and EXACTLY 5' Center-Center.

These PICs are for 'demonstration' only. I don't shoot from my yard toward a road or neighbors house; just so U know.



I made a taller and narrower target holder so that bullet flight is HIGHER than the screens. Also the holder will fold down and clear the STOP screen.

The III system can be used WITH or WITHOUT the diffusers.



Since the 33 -- II screens were not designed for the diffusers, I've never used them and haven't had any problems. In the coming days I'm going to run a few testS using a couple of 22 LR, 1 handgun and 1 rifle. I want to see if there is any diff between using and NOT using the diffusers.

I have a pile of dirt in my pasture that I use for a backstop and I can shoot from very close or back out around 200 or so yards. I'm looking forward to giving the Skyscreen IIIs a workout.


Jerry

You've blown exactly two more primers than I have, but I've only been doing it for 45 years or so. Anyway, my post was that as a rule, I've found that lots vary less by volume than weight, not whether hot loads and powder variations can cause problems. We already know this.

jstevens-

you are 4 yrs my senior at handloading.

I guess it's

to each...his own


Jerry

Hey Cator-

Have you found out anything in particular?
Still interested in your results.

Jerry

Ahh! Work and life has been too hectic. I got the ammo loaded and sitting on my bench, but time to get to the range has been non-existent. But I have not forgotten to update, I will PM you when I get it done, hopefully soon!

Thnx but I am not rushing ya.

Sometimes life gets in the way of 'important' stuff.<grin>

I have some load development and graphing to do as well but we've had a WHOLE lotta rain. Hopefully the WX will cooperate so I can get it done soon.

If you'll update us here is sufficient.

Hope you find good answers.


Jerry

Hello Mr. Factory Ammo, it's been awhile.....

16bore -
The following quote of mine is from P 4, 2-19-16



That WAS the problem/result. Don't ask me how I know, but I do.


Jerry

No quite sure I'm following you or if you read between the lines of my post.