Why Not Blue Dot or ?

[sqlbullet]

If you preserve overall length by removing part of the barrel and replacing it with compensator/brake you may loose a few fps.  But, you have effectively shortened the pressure bearing part of the ride.

If you attach it to the end increasing the overall length of the gun, I doubt it would have any impact at all.  If it did it should be a tiny increase.

It can have a positive impact on accuracy.  It helps normalize the forces that occur as the projectile leaves the barrel, resulting in more stability.  In rifles this can be significant, taking a 1 MOA gun to .75 or better.  In handguns I expect the difference would be hard to quantify.

[EdMc]

/quote]

Thinking about this, someone in another thread asked about measuring the casing after sizing......with the Hornady dies mine came out one or more thousandths more than anyone else posted. ) 0.419 as I remember.....the die measures 0.416 with a pin gage. I know the brass 'springs' back so I wonder about the internal ID of other dies. Probably meaningless mental masturbation.

[Yondering]

The spot you need to be measuring is not touched by the resizing die (unless you're talking about a push through die). Measure the area immediately in front of the extractor groove, not farther up the case where it gets resized.

[EdMc]

Thanks, I get that.........the other was just mental rambling out loud, sorta. Like I said, meaningless.

[EdMc]

Okay, so I tried some Power Pistol. Same stock G20SF, new Starline, WLP, 180 XTP, 1.260 coal, 0.419 crimp.

8.5 gr Power Pistol

1136
1142
1152                       AVG   1150
1158
1164

Right on 'book' velocities for the bullet and amount of powder. Makes me think something isn't right with lot of Blue Dot I bought. I know you can have a variance with different lot numbers on any powder but the BD is ~ 100 fps slower than other reports. Or, is that a normal variance?

[sqlbullet]

Doesn't seem normal to me.

[Yondering]

Doesn't seem normal to me either. You might give Alliant a call, see if they know of any issues with that lot of powder.

[EdMc]

I tried calling and got an answering/leave a message system. I find that hard to believe for a large company, unless this is annual vacation week. Anyway, I sent an email to their 'Ask the Experts' contact on the Alliant website.

[The_Shadow]

You might want to try different primers,  Using CCI350's or other magnum primers with Blue Dot may bring the velocities up and tighten up ES and SD.  I have seen some variances using 300's or non magnum primers with Blue Dot.

[EdMc]

You might want to try different primers

Well, other than using Starline cases instead of Hornady it's all the same as the loads in the Hornady manual. I'm over 100 fps slower with BD but dead on their velocity with PP. If anything, with the slightly shorter Glock barrel, my chrono might read a little high going by that. I did get a reply from Alliant wanting a little more information so I'll wait and see what they have to say. Not that it's a big deal, I'd just like to know why the large difference when using BD and not with another powder. Thanks.

[EdMc]

To anyone still following this never ending saga  this is the reply from Alliant:

"I cannot explain the lower velocity with Blue Dot.  If could be that the faster burning Power Pistol is more efficient in your barrel length."

My question was that a max 'book' load of Power Pistol was at book velocities while a max load of Blue Dot fell ~ 100 fps short and had anyone else questioned that particular lot of Blue Dot. I guess I'll try the same load in my new Smith 1006 and see if I find a major improvement in velocity. Then I'll know for sure if it's the pistol or the powder.  

[Yondering]

Well, I tried a few more loads over the chrono. Same new Starline brass, 180 XTP, WLP, 1.260 and 10.7 gr BD individually weighed etc. The only change was a little more crimp...0.419. Avg. velocity was 1128 fps this time, only slightly better than the previous 1092.  Beats me, maybe I'll try some Power Pistol I have and see how close it comes to book values.

Have you slugged the bore in that barrel? I wonder if a slightly loose/oversized bore is contributing to low velocity, where the faster Power Pistol might not be as sensitive to it.

Looked back at my load data; I haven't used the 180 XTP's, but a very similar load of 180 JHP (Montana Gold) at 1.260" over 11.0gr BD and a WLP was doing 1300 fps from a 4.6" Storm Lake barrel.

[EdMc]

[/quote]

Have you slugged the bore in that barrel? I wonder if a slightly loose/oversized bore is contributing to low velocity, where the faster Power Pistol might not be as sensitive to it.

Looked back at my load data; I haven't used the 180 XTP's, but a very similar load of 180 JHP (Montana Gold) at 1.260" over 11.0gr BD and a WLP was doing 1300 fps from a 4.6" Storm Lake barrel.
[/quote]


No, I haven't, although it might be a good idea. Taterhead, in a previous post, noted my results with 9.0 gr of Longshot (avg-1198fps) were somewhat close to his. Longshot being much closer to Blue Dot than Power Pistol in burn rates makes me still look at the powder being the reason.

I think I still have about five rds of the Blue Dot load......if I can catch my neighbors at work tomorrow, I'll try them in the Smith. That should tell me something......maybe?

Normally to use the chrono I have to drive up to a friends place, when he's home, as the indoor range I use obviously doesn't allow using the chrono.

[Yondering]

I think you're right that you got a slow lot of powder. Still worth slugging the bore though, and this is useful info if you plan to shoot any cast bullets through it too.

[EdMc]

I shot the remaining five rounds out of the Smith today. Average was 1181, about the difference you'd expect from the slightly longer (5 inch) barrel. No excuse, but I was in a hurry and hit my chrono    fault is all my own. May it R.I.P. :'( Obviously was able to recover the data.

What and where could I find soft lead to use to slug the bore? I've never done it before.......about time I tried.