H4350 lot inconsistencies

[lennyo3034]

I was wondering if other people noticed variations in velocity based on different lots of H4350.

I developed a load around this time last year in 6.5 creedmoor using 41.8 grains of H4350 and velocity right 2750. I have since used up all that powder and have a new 8lb keg. Using the same load, I am now seeing closer to 2790 fps. Accuracy has dropped off somewhat, probably due to the change in node.

 

[17874]

You always have to adjust a little bit after switching to a new lot of powder. Just load it down until you achieve your desired velocity. Could also be partially due to your chronograph depending on the model and conditions (temp) when velocity was measured. Even with H-4350 you will see an increase in velocity with an increase in temperature.

 

[padom]

My load was dead on between the last 2 8# jugs.

 

[Darkside-Six]

My load was dead on between the last 2 8" jugs.

Mine as well.

OP. How many rounds down the tube in the last year? Could be changes in your barrel and theist erosion. Lands getting pushed back.


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[GhengisAhn175]

It could be many things including environmental.

Unless you have exact kestrel data that shows a very minimal increase it could just be that or any other combination.

Anytime you switch lots of any component always verify. If it's faster or slower, adjust accordingly. Should be very simple since you just need to tweak down a hair

 

[lennyo3034]

I recall the temperature being very close. I do have kestral data, unfortunately I can't find my damn data book.

I did not shoot the rifle a whole lot last year, maybe 750 rounds.

 

[Fursniper]

I was wondering if other people noticed variations in velocity based on different lots of H4350.

I developed a load around this time last year in 6.5 creedmoor using 41.8 grains of H4350 and velocity right 2750. I have since used up all that powder and have a new 8lb keg. Using the same load, I am now seeing closer to 2790 fps. Accuracy has dropped off somewhat, probably due to the change in node.

YOU GOT A NEW 8LB JUG OF H4350??! You may be the only guy on the continent to manage that small miracle lol! Please tell what magic spell you concocted to pull that off......

 

[padom]

Its out there. I got 4 new 8# jugs...

 

[6.5x47 Guy]

H4350 varies quite a bit from lot to lot. Just tapped into a new 8lber and had to go up .6 grains to maintain my velocity. That's the most I've ever seen usually it's only a few tenths up or down.

 

[Supersubes]

Ive found it to be spot on from jug to jug. My old theory was that an old large jug of powder would have absorbed some moisture over it's life, and was a shade heavier per kernel, which would over time lower velocities. Switch to the new powder, and you jump right back up to where you'd been.

Lately though, i'm inside 10fps lot to lot, and some of that powder was years old. Out the window that theory goes....


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[steve123]

H4350 varies quite a bit from lot to lot. Just tapped into a new 8lber and had to go up .6 grains to maintain my velocity. That's the most I've ever seen usually it's only a few tenths up or down.

I've found nearly every 8lb jug of a different lot to be slightly off . Ruining brass and dope being off was a good teacher.

I thought I read somewhere Hodgdon has a 5% tolerance in burn rate ??? I think it was the same article that stated Vihtavuori tolerance was much more consistent from lot to lot but then the H extreme powders are less temp sensitive so...

 

[Sendit6.5]

Ive found it to be spot on from jug to jug. My old theory was that an old large jug of powder would have absorbed some moisture over it's life, and was a shade heavier per kernel, which would over time lower velocities. Switch to the new powder, and you jump right back up to where you'd been.

Lately though, i'm inside 10fps lot to lot, and some of that powder was years old. Out the window that theory goes....


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I keep a desiccant pack in all my powder jugs (and even in my Chargemaster when I leave powder in it for a few days) and I change them out every 3-4 months. They're super cheap in bulk on Amazon and it makes me worry less about moisture accumulation.


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[lennyo3034]

Not a bad idea.

 

[lennyo3034]

I will back off on the load to try to get my velocity back down. Unfortunately I have a match this weekend and don't have time to test. What load do you guys think will drop me back to 2750? 41.8 grains is giving me 2790 now. I was thinking of loading to 41.6 and just going to the match with that.

 

[GhengisAhn175]

Drop to 41.4 or 41.5

thst may may not guarantee because we don't know if it's due to velocity differences.

 

[GhengisAhn175]

If you're dead on in your node, lot variations shouldn't account for a huge shift. There's always lot variation. But you have to be absolutely sure it's powder alone (not anything else).

If you get shot completely out of a good known load it's more than powder.

 

[padom]

If you're dead on in your node, lot variations shouldn't account for a huge shift. There's always lot variation. But you have to be absolutely sure it's powder alone (not anything else).

If you get shot completely out of a good known load it's more than powder.

Exactly!

If you perform proper load development and ensure your right in the center of the node lot to lot variations shouldnt matter. Thats why we spend the time to find the dead center of a node...

I retest my load every time I open a new jug of H4350 and always the same result. Same boring clover leaf and single digit SD's... I even leave my powder in my H4350 sometimes for weeks at a time then drop more charges to make more ammo and same results on target. I do have a dehumidifier and central air in my reloading room so leaving powder in my CH doesnt change anything.

 

[Themagundaog]

I as well have noticed velocity jumps from lot to lot

 

[Texascbr]

I just opened a new 8lb jug of H4350 and loaded 20rds of the new powder with the remainder of my old powder batch separately to compare using the same exact prep and components. When testing alternating 3 groups of 5 shots for each batch of powder during the same range session I saw a ~20fps decrease in speed for the new powder but still single digit and sub half MOA groups. Went from roughly 2870fps to 2850fps average. I worked up the loads with the prior powder using the Saterlee method.

I would like to recover that lost 20fps and will likely try a testing an additional .2 and .4 grain powder increase.

Thoughts?

rifle AI AT, 25” Bartlein

original load
42.0 H4350
Lapua Brass
CCI 450 primers
Hornady 140 ELD-M

Also curios what to do with my DT‘s load which prefers Berger 130’s that was worked up with the same prior powder?

rifle Desert Tech SRS! 25” Hawk Hill
42.5 H4350
Lapua Brass
CCI 450 primers
Berger 130 Hybrid

 

[clcustom1911]

I just opened a new 8lb jug of H4350 and loaded 20rds of the new powder with the remainder of my old powder batch separately to compare using the same exact prep and components. When testing alternating 3 groups of 5 shots for each batch of powder during the same range session I saw a ~20fps decrease in speed for the new powder but still single digit and sub half MOA groups. Went from roughly 2870fps to 2850fps average. I worked up the loads with the prior powder using the Saterlee method.

I would like to recover that lost 20fps and will likely try a testing an additional .2 and .4 grain powder increase.

Thoughts?

rifle AI AT, 25” Bartlein

original load
42.0 H4350
Lapua Brass
CCI 450 primers
Hornady 140 ELD-M

Also curios what to do with my DT‘s load which prefers Berger 130’s that was worked up with the same prior powder?

rifle Desert Tech SRS! 25” Hawk Hill
42.5 H4350
Lapua Brass
CCI 450 primers
Berger 130 Hybrid

Increase by .3 with the 130 and .2 with the 140. Try it out.

I had 4 pounds each of 2 lots and mixed 'em up in the same container. 41.4-41.5 under 142 SMK and 147 ELDm does extremely well as does 42.4-42.6. 42.8 under 130 TMK, 130 RDF, 130 Berger Hybrid does very well

The above loads work well in a Proof Research prefit barreled 6.5 Creedmoor Ruger Precision Rifle (short throat), and Tikka T3X Tac A1 (mile long throat LoL).