Hot retumbo lot?

[txsendero]

Any body experience a hot lot of Retumbo powder? I just got another can, and had to lower the charge 2 full grains to get the same velocity as I was getting before in 7mm Rem Mag (72 grains down to 70 grains).

 

[JUDD]

Same temp outside each time you shot I assume?

I shot differant lots and never had this problem...however temp did change things a bit from time to time....

 

[txsendero]

Yes, same temperature range, 70 - 80 degrees F.

 

[dustybrown]

Have you ruled out other factors ? I have seen a gun build preasure and with that mv increase as well. A fouled barrel can some times cause this... bullet seating closer to the lands can do the same.... increase MV.. some brass can have different capacities ie... rem vs. nosler vs. winny brass.
You didnt say how much the MV had increased ? I assume quite a bit dropping two grains...to get the same. Also dont take the chrono as gospel... did you see a POI change at longer ranges ?

 

[Jumpalot]

Not Retumbo, but I had the same problem with H1000. I had to drop my load about 3 grains and still had slightly flattened primers and less velocity.

 

[Moman]

I had the same problem recently with H-1000 as well. Dropped from 92.5 to 91.0 grains to keep the same velocity and accuracy. This definately happens from time to time with different lots. It's always a good idea to re work up your loads each time you change lot numbers.

 

[txsendero]

Have you ruled out other factors ? I have seen a gun build preasure and with that mv increase as well. A fouled barrel can some times cause this... bullet seating closer to the lands can do the same.... increase MV.. some brass can have different capacities ie... rem vs. nosler vs. winny brass.
You didnt say how much the MV had increased ? I assume quite a bit dropping two grains...to get the same. Also dont take the chrono as gospel... did you see a POI change at longer ranges ?

Fouled barrel?.....nope, cleaned well before shooting.
Bullet seating length?......nope, same as before, measured with Hornady LnL OAL gauge.
Different brass?.......nope, all the same lot of WW brass, all fired the same number of times.
MV increase?.........Don't know, I started at 2 grains below where I was before with 72 grains, and once I saw the same velocity with 70 grains, I didn't go any higher, also shot it at 600 yards with 2 grains less powder and drops were right on.

 

[dustybrown]

Hmmm. retumbo has allways been good for me... but now im wondering...LOL im on my last of 5 bottles of lot # 4779 dang !!!! should have bought them all. But I didnt want to be "that guy" who emptys the shelf every time they get it in.