IMR 4895 vs H 4895

[Mozella]

My tests show that IMR 4895 shoots well in my 6mm BR Norma @ 600 yds, 2850 fps. However, it seems that more people are using H 4895.

I need to purchase more powder soon. Should I expect equal or better results with H 4895? I know they're not the same but I don't mind doing a mini-load work-up.

Some use Vihtavuori N-540 or N-140, both of which I tested, but IMR 4895 works better in my 28" 1:8 twist barrel.

Or should I consider Reloder 15 or IMR 4064, neither of which I've ever tested in any rifle.

 

[Laurie]

Generally you can get higher MVs from the IMR version provided you can get enough of it into the case. It's a little bit slower burning than H4895, but I suspect the heavier loads used and higher velocities aren't just down to that.

I've never tried it in the BR myself (had very good results in some larger cartridges like 308 Win) and I would expect it to do well with heavier bullets. I'm not sure the case will hold enough of it though to get to maximum pressures, short of using a 20-inch plus length drop tube on the powder funnel. (Don't laugh! I know one top 6BR shooting benchrest competitor who does exactly this to get enough of another slightly bulky, slightly slow burner into the little 6BR case.)

 

[Mozella]

Generally you can get higher MVs from the IMR version provided you can get enough of it into the case. ... snip....... I'm not sure the case will hold enough of it though to get to maximum pressures, ...... snip........

I found the best precision at 30.18 grains, just a tad below Quick Load's "Dangerous DO NOT USE" warning. I don't like getting into the DO NOT USE range where the screen starts blinking magenta and my Mom's voice starts screaming from the grave, "You'll Shoot Your Eye Out", but that's just me.

It's only a 96.2% fill ratio. No problem getting it all in the 6mm BR case, so I'm a bit confused at your comment.

 

[ShootDots]

I suspect that most people who opt for H4895 over the IMR version do so for 2 reasons: 1.) shorter powder kernels; and 2.) The H version is an "Extreme" version where temp stability is supposedly more consistent in various temp swings. The first reason is a valid reason. The kernels are smaller, hence a "tighter" or "higher" load density. Probably not significant in "normal" size cases, like a 308 or larger. However, in small cases like a .223 or a 6BR or even possibly a Dasher sized case, the higher load density may (and I mean MAY) be of benefit. The IMR version is pretty dang temp stable, as is IMR 4320, IMR 4831, and IMR 7828. Are they as "stable" as the "Extreme" versions, I don't know>>>all I do know is, is that I have never had temperature swing problems with either of the IMR versions listed in this reply. Also, it appears to me that IMR 4895 will "generally" produce a bit higher velocities than the "H" version..

 

[Liven The Dream]

One more thing to look at pressure ??

In a .308 case IMR 4895 goes over pressure rating with a 155 bullet
H 4895 with the same load is under the rated Pressure .
Hope this of some help ?

 

[Ned Ludd]

I have tested IMR4895 in both .223 and .308 loads with heavy bullets (90 gr and 185 gr, respectively). Both are cases in which I regularly use H4895. If you load to OBT nodes, IMR4895 will generally net you about 20-30 fps greater velocity than H4895 on an OBT node. In my hands, the pressure differential at the OBT nodes is negligible, in fact, IMR4895 is predicted by QL to give lower pressure in one of my loads, even though the velocity is slightly higher.

With regard to Laurie's comment about case volume and IMR4895, I had an issue with a compressed load at the OBT node in virgin Lapua .223 brass. The cases were definitely filled up and seating bullets was challenging in the OBT load in virgin brass. The average weight of a kernel of IMR4895 is about half again the weight of a kernel of H4895, and slightly higher than a kernel of Varget. I find the IMR4895 kernels are also more irregularly shaped than H4895 or Varget. Together, those two parameters suggest to me that IMR4895 may not pack into the case quite as well as H4895, which has slightly smaller and more regularly-shaped kernels. In the case of the .223 load, once the brass had been fire formed and resized, the increase in case volume was enough to take care of the compression issue. It was only an issue in virgin brass.

The main reason I have not routinely used IMR4895 in loads for competition as yet is a concern about the temperature-sensitivity. According to the temperature data I have found, IMR4895 is more sensitive than H4895 or Varget. It is still generally much better than double-base powders, so it may not be a problem at all. Because of the temperature variations where I shoot and because I was unsure about it, I haven't chosen to shoot it in matches as yet. I am happy to hear the reports above; it sounds like it's not much of a concern. In general, a 20 to 30 fps increase in velocity doesn't mean a huge amount. However, as long as the precision and ES/SD are comparable (which they have been), and temperature-sensitivity isn't an issue, I'll take the extra velocity from IMR4895 any time, especially in a .223 shooting 90s at 1000 yd. Every little bit helps.

 

[1shot]

I just finished a load work up in a BRX using moly coated 105 gr. bullets that included both H-4895 and the IMR version. I did ladders tests in .3 gr. increments with both powders.
The IMR pressured out at 2,884 fps. and the groups were horrible from the bottom to top end loads.
The H-4895 netted me 3,041 fps. with an ES of 6.
I will be taking that load to a mid-range match this weekend to see how it performs for 60+ shots.
I hope this helps,

Lloyd

 

[dkhunt14]

I just finished a load work up in a BRX using moly coated 105 gr. bullets that included both H-4895 and the IMR version. I did ladders tests in .3 gr. increments with both powders.
The IMR pressured out at 2,884 fps. and the groups were horrible from the bottom to top end loads.
The H-4895 netted me 3,041 fps. with an ES of 6.
I will be taking that load to a mid-range match this weekend to see how it performs for 60+ shots.
I hope this helps,

Lloyd

Are You comparing actual groups or just the chrono readings or both? Matt

 

[rocketron]

I just finished a load work up in a BRX using moly coated 105 gr. bullets that included both H-4895 and the IMR version. I did ladders tests in .3 gr. increments with both powders.
The IMR pressured out at 2,884 fps. and the groups were horrible from the bottom to top end loads.
The H-4895 netted me 3,041 fps. with an ES of 6.
I will be taking that load to a mid-range match this weekend to see how it performs for 60+ shots.
I hope this helps,

Lloyd

What were the charge weights for the H4895?

 

[Travelor]

I think you will find your happy place with Varget at 30 grains.

 

[1shot]

Matt,
I'm recording both groups and chrono data.
Travelor,
32.9-33.7 spread velocities between 2,850 and 2,949 fps. All groups were 1.5+- moa and scattered.

 

[Mozella]

I think you will find your happy place with Varget at 30 grains.

Actually, best precision in my gun using Varget is at a charge weight of 30.70gr and although the MV is good at 2905 fps and the SD quite low, the group size is not quite as good as with IMR 4895.

 

[1shot]

What were the charge weights for the H4895?

PM sent

 

[sofarfrome]

I think you will find your happy place with Varget at 30 grains.

Yes, don't forget the Varget. Heavy bullets in 22 or 6 BR love this powder.