Dirty barrel and sd relations ?

[DLT]

So another rifle of mine that shot o so well has had a jump in sd/es. Spreads are now over 30fps where they used to be -15fps over countless trips to the range. The only components that’s changed is my lot of powder of H4350. I ran out of it and opened a new 8lb jug so I hsve come here for suggestions and advice.
My old load ran pretty consistently between 3030 and 3045 with 38.5gr in temperatures like we’re currently experiencing. Now my load is 3000.
I did run another powder test but had to run up to 39.2 to achieve that velocity. At that charge it shoots just ok and my numbers have doubled. I’m not a huge numbers man but it’s not grouping like it once was. I load in the same steps every time including annealing and full length sizing. I have not cleaned it lately eh maybe a hundred rounds since it was scrubbed. It’s a 6xc with around 800 rounds down the pipe Thanks dudes. Oh and primers are cci 450s with Peterson brass. Also about the same time I did start shooting with a suppressor. It has changed my point of impact but I have not shot it across the Garmin without it installed

 

[David Christian]

A suppressor will extend the harmonics on a barrel as well as speed up the muzzle fps. Not exactly starting from square one with load dev, but the load will need to change.

 

[mgunderson]

I often start testing the next jug of powder before the first jug is gone. Just a few rounds to double check the speed and help answer these questions when I still have options. Just a suggestion for next time. Additionally, your seating depth might need slight tweak with that many rounds on it.

 

[10XSHOOTER]

If you have more than one jug of the same powder MIX THEM.
you will then have several pounds of the same mixxture.
I have blended 5 8lb jugs of H4350 all were different lots.
I now have 40# of all the same mix.

 

[DLT]

If you have more than one jug of the same powder MIX THEM.
you will then have several pounds of the same mixxture.
I have blended 5 8lb jugs of H4350 all were different lots.
I now have 40# of all the same mix.

That’s what I did with the 3 or 4 singles I had. I mixed them but like all good things I ran out

 

[DaveTooley]

With 800 rounds on the barrel a seating depth change might be in order if you have the space.

 

[DGP4]

Obvious culprit is the new powder. Did you shoot with the old powder using the suppressor without any change?

 

[DLT]

With 800 rounds on the barrel a seating depth change might be in order if you have the space.

I do have the space to go forward and back with the long neck on the xc. Original loading is .025 off the lands

 

[DLT]

Obvious culprit is the new powder. Did you shoot with the old powder using the suppressor without any change?

If I did it wasn’t much. And I sure didn’t shoot across my Garmin

 

[6.5 forever]

I often start testing the next jug of powder before the first jug is gone. Just a few rounds to double check the speed and help answer these questions when I still have options. Just a suggestion for next time. Additionally, your seating depth might need slight tweak with that many rounds on it.

I have started doing this. Takes the stress out of the change and makes comparing easier.

 

[SpencerC87]

I always have to wonder how much of the variation in different lots or new vs old jugs of powder have to do with humidity variation.

 

[6.5 forever]

I always have to wonder how much of the variation in different lots or new vs old jugs of powder have to do with humidity variation.

Some good shooters say it has a lot to do with it. I've started taking the lid off new jugs several days before I start using it.

 

[DLT]

Some good shooters say it has a lot to do with it. I've started taking the lid off new jugs several days before I start using it.

I wish this lot was hotter than it is. I could have did the same to hopefully bring its fps down to where I was at. But it’s slower

 

[boltfluter]

Sounds like 2 changes happened at once. If you have the ability, isolate them, and test each one separately. New powder and no suppressor. See how it does and then add the suppressor to the mix. My suppressors have either made no difference or have improved the accuracy. And a little gain in speed. Good luck and keep us posted.
Paul

 

[DLT]

Sounds like 2 changes happened at once. If you have the ability, isolate them, and test each one separately. New powder and no suppressor. See how it does and then add the suppressor to the mix. My suppressors have either made no difference or have improved the accuracy. And a little gain in speed. Good luck and keep us posted.
Paul

Oh I’m going to. I really enjoy shooting with it. I wish I could get my speed and numbers back like they were

 

[Coyotefurharvester]

Was the barrel muzzle threaded new? I don't recall a load developed without a muzzle device not shooting better with a suppressor. If you had the muzzle threaded after your load work, for the suppressor, you have another factor to consider.

 

[DLT]

Was the barrel muzzle threaded new? I don't recall a load developed without a muzzle device not shooting better with a suppressor. If you had the muzzle threaded after your load work, for the suppressor, you have another factor to consider.

No it’s always been threaded just been shot with a thread cap installed

 

[Ringostar]

I wish this lot was hotter than it is. I could have did the same to hopefully bring its fps down to where I was at. But it’s slower

Thinking about this comment. If the humidity of your new powder is higher, then it will be more dense. Therefore less kernels to equal same weight as drier powder. The denser powder will be slower, as you’re experiencing. A drier powder will have more kernels per weight, and also burn faster. This could explain what you’re experiencing. So leaving some powder open could dry it down. You can experiment with a half pound open to dry, then load test rounds of each to equal weight. Then check velocity of each. Drying might get you back where you were at.

 

[DLT]

Thinking about this comment. If the humidity of your new powder is higher, then it will be more dense. Therefore less kernels to equal same weight as drier powder. The denser powder will be slower, as you’re experiencing. A drier powder will have more kernels per weight, and also burn faster. This could explain what you’re experiencing. So leaving some powder open could dry it down. You can experiment with a half pound open to dry, then load test rounds of each to equal weight. Then check velocity of each. Drying might get you back where you were at.

Think where I am in western nc it will dry much at all ? I figured it would draw moisture

 

[Ringostar]

I’ve seen video from Keith Glasscock using humidor packs and desiccant packs to experiment with humidity levels in powder. Winning in the wind on YouTube, check it out. Maybe desiccant packs in a one pound container would help. I would definitely clean the barrel and test seating depth again though.