IMR4895 vs H4895

[lennyo3034]

I am going to be loading for a .223 bolt gun and Valkyrie soon. It seems H4895 is a popular powder for these calibers. However I have 10 pounds of IMR4895 collecting dust. My understanding is that it's more temperature sensitive and might burn very slightly slower.

Has anyone tested the two? Are they close enough or should I look into selling it and buy Hodgdon?

 

[Engine 22]

You are correct on both. IMR 4895 is just a tad slower according to Hodgdon's relative burn rate chart and IMR 4895 is temperature sensitive. H4895 is a Hodgdon Extreme powder and is very temperature stable. In my opinion, H4895 is the better choice of the two.

 

[spife7980]

The number to the right of the type powder below is the feet per second change for each degree of temp change.
.

Can you clarify this part? Never heard that before.

 

[lennyo3034]

Look at the chart to the right of the powder type, the larger the number the more temp sensitive the powder is.
Double base ball powders with nitroglycerine are more sensitive to temp change than single base powders.
The newer IMR powders are less temp sensitive and have copper eraser additive in the powder. (extreme powder plus copper erasing)

H4895 = 0.23 fps change for each degree of temp change.
IMR-4895 = 1.10 fps change for each degree of temp change.

RL15 = 1.52 fps change for each degree of temp change. (Caliber 7.62mm, NATO, Ball, Special, M118LR)
IMR-4064 = 0.45 fps change for each degree of temp change. (Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0)

Bottom left of chart
Temperature stability is represented in fps/F

Which chart are you referring to? Can you post a link?

 

[spife7980]

The chart in post #3 above, in my first post.

You must be using imgur, the pictures havent been showing up for anyone other than the poster who is signed into the imgur account lately.

 

[lennyo3034]

Now I see, useful chart.

 

[CanSniper]

Super useful! Thanks! What is the source?

 

[Deleted member 10043]

Good info. What is the purpose for different manufacturers using the same last four numbers? Example, AA4350, H4350, and IMR4350.

 

[Supersubes]

Good info. What is the purpose for different manufacturers using the same last four numbers? Example, AA4350, H4350, and IMR4350.

Id guess it has to do with the target burn rate. One knows that imr 4350 an h4350 are very close in burn rate. Nearly interchangeable actually.

Hodgdon data states that they’re
within .2grns of each other at max pressures, and make near identical velocities. The AA variety is aiming for the same.

 

[Deleted member 10043]

Or closer to the chemical make up of the powders that allow them to use identical numerals.