Has H4350 changed in the past few years?

[Paulyester]

I see old forum posts about using up to 43.5gn of H4350 using the 140 ELDM in a 24 in barrel. I noticed that Hornady's max charge has come down to recommended max load of 41.0. I watched a video the other day with a guy testing some H4350 he was getting low 2600 with a 24 in barrel and 41.8gn of powder. I'm getting 2720 with 40.3 and if I go to 41 I'm getting pressure signs and close to 2800 fps

 

[ballisticdaddy]

This is exactly why it is recommended to start low and work up to a safe charge weight. I can speak from experience that a charge weight of 43.5G of H4350 in a 6.5 Creedmoor is a HOT load. Most of my rifles have been no more than 42.0 grains in a 24" barrel. Below is the load data from Hodgdon for 6.5 Creedmoor using a 140 grain bullet with H4350:

 

[Bill Norris]

This is exactly why it is recommended to start low and work up to a safe charge weight. I can speak from experience that a charge weight of 43.5G of H4350 in a 6.5 Creedmoor is a HOT load. Most of my rifles have been no more than 42.0 grains in a 24" barrel. Below is the load data from Hodgdon for 6.5 Creedmoor using a 140 grain bullet with H4350:

View attachment 1623242

Worked up 6.5 C M loads with H-4350 and 140 class bullets for a close friend of mine last spring. 42.0 gr. was a great load for accuracy @ 2750 FPS but I would not want to go with any more powder than that.

 

[kyotekiller25]

I blew 2 primers out of a 6 creed with H4350 at 1g under hornadys book max with the 108 ELDMs during my load work up.

I use 40.2g now for right at 3000fps. And that's also from a 27" 8 twist Brux. Factory 108s clock 2980fps.

I'm not quite sure how some guys are running 42-42.5g of H4350 with a 108g at 3150-3200 from a 6 creed with 24-26" tubes without popping primers...

 

[whatsupdoc]

Different lots of powder and bullet case and chamber combinations will provide
variable pressures and velocities. This is not new it is reloading 101.

I have reloaded many thousands of rounds of 6.5 creed and there have been times when switching to a different lot of powder had negligible effects and other times my velocity varied 80 fps.

You need to adjust your load for different lots of almost any powder.

 

[Bill Norris]

^^^^^^^ This

 

[Bill K]

Different lots of powder and bullet case and chamber combinations will provide
variable pressures and velocities. This is not new it is reloading 101.

I have reloaded many thousands of rounds of 6.5 creed and there have been times when switching to a different lot of powder had negligible effects and other times my velocity varied 80 fps.

You need to adjust your load for different lots of almost any powder.

Has it changed over time. No more than it does between lot to lot, I would say.
Anytime you change from one lot or any other component in your loading, you need to start lower and work back up. Every chamber is different from others and you work up in YOUR rifle/chamber to be safe.

 

[358WCF]

I see old forum posts about using up to 43.5gn of H4350 using the 140 ELDM in a 24 in barrel. I noticed that Hornady's max charge has come down to recommended max load of 41.0. I watched a video the other day with a guy testing some H4350 he was getting low 2600 with a 24 in barrel and 41.8gn of powder. I'm getting 2720 with 40.3 and if I go to 41 I'm getting pressure signs and close to 2800 fps

H4350 lot to lot differences can be rather dramatic. I first noticed this during the initial covid cluster-coitus of component scarcity. Using two different 1# cans of H4350 bought from different sources about a month apart, the newer one showed about 200fps slower with serious accuracy loss on the same day with all other components identical in a 22-250 Ackley. The above was only kind of disappointing, but could have been pretty exciting going in the other direction with a max load.

Further testing with the 2 lots of powder (& expanded to include every other can of anything called 4350 in the closet) in that & 3 other cartridges of various sizes & calibers showed similar results; some of which were surprising. That & it kept me out of trouble for a couple of days.

Edit: Looks like I took to long writing my response & eating lunch. Ay yi yi...

 

[Park ranger]

A shooting buddy has a keg of H4350 that acts more like varget with 140’s.

 

[Clancy]

I don’t know how many different brands of Creedmoor brass there are. At least a dozen. The specs are different on all of them.

Factor in freebore, chamber integrity, barrel cleanliness and scale error and you really shouldn’t be getting a load off the internet.

Keep this in the back of your mind.

I did load work on two 22 Creedmoors from the same Reamer, and a load 8.5 grains apart produced less than 100 fps difference. The only things- and I mean the ONLY things- that changed were the lots of components.

Start low and work up isn’t a suggestion. It’s a safety precaution. It’s a golden rule. It’s even a matter of life and death.

 

[Paulyester]

H4350 lot to lot differences can be rather dramatic. I first noticed this during the initial covid cluster-coitus of component scarcity. Using two different 1# cans of H4350 bought from different sources about a month apart, the newer one showed about 200fps slower with serious accuracy loss on the same day with all other components identical in a 22-250 Ackley. The above was only kind of disappointing, but could have been pretty exciting going in the other direction with a max load.

Further testing with the 2 lots of powder (& expanded to include every other can of anything called 4350 in the closet) in that & 3 other cartridges of various sizes & calibers showed similar results; some of which were surprising. That & it kept me out of trouble for a couple of days.

Edit: Looks like I took to long writing my response & eating lunch. Ay yi yi...

This is closer to what I experienced and it makes sense because my first #1 bottle of H4350, all my notes said I was getting a good accuracy node at 41.7 gn. The second #1 bottle I loaded 41.7 and I blew a primer out and damaged the ejector pins. This bottle I can only get about 40.9 before I see clear pressure marks. 40.6 is the sweet spot now.

 

[Keith Glasscock]

I've been through more lots of H4350 than I care to count. They all were relatively similar with only a tenth or two change needed to maintain velocity. After I learned about powder humidity (water content), all of the differences became much, much smaller (almost impossible to detect).

I never understood shooters that would leave the cap off their powder for a couple of weeks before using it until I figured out what they were really doing. They were establishing a common humidity environment for their powder...

I'd recommend using a two way humidity control product (Boveda comes to mind) with your powder. It will stabilize the stored powder to a consistent humidity level. Here is the big hint: It takes time, measured in days/weeks to get a few pounds of powder equalized in an environment. Start early prepping the next batch/lot.

 

[X Count]

I see old forum posts about using up to 43.5gn of H4350 using the 140 ELDM in a 24 in barrel. I noticed that Hornady's max charge has come down to recommended max load of 41.0. I watched a video the other day with a guy testing some H4350 he was getting low 2600 with a 24 in barrel and 41.8gn of powder. I'm getting 2720 with 40.3 and if I go to 41 I'm getting pressure signs and close to 2800 fps

Yes, myself and others have found some very fast batches in the last few years. 60-80fps which could equivalent to around 2gr of powder.

 

[ShtrRdy]

Something else that could be a factor. If you live in a dry climate and the powder you're using is exposed to the low humidity, the energy of the powder increases.

How does humidity affect powder?

You may have heard about a relationship between humidity and bullet velocity either in a book, on a reloading forum, or from a crusty benchrest shooter right after saying they get better ES/SD&#821…

chronoplotter.com

 

[Chuckhunter]

Different lots of powder and bullet case and chamber combinations will provide
variable pressures and velocities. This is not new it is reloading 101.

I have reloaded many thousands of rounds of 6.5 creed and there have been times when switching to a different lot of powder had negligible effects and other times my velocity varied 80 fps.

You need to adjust your load for different lots of almost any powder.

I agree, that's why I own and use a chronograph, to see the different burn rate and max pressures when changing powder lots. Avoids wasting components and pressure problems.