Powder Test 7mm Rem Mag

[Mike6158]

Well... One of these things, H4350 and IMR4350, is not like the other...

Same rifle. Same charge weight. Same bullet. Same seating depth. Slightly cooler-ish. Different primer. I switched primers to Winchester WLRM. That kind of screws up the "sameness" but it is what it is.

H4350 (3,045 - 3,100 fps)

Shot string #9 is suspect imho.

IMR 4350 (2,985 - 3,040 fps)

 

[VinceMule]

H and IMR are two different animals. I think that you are over-igniting the powder with the Win mag primer, but accuracy in your rig tells all.

I shot quite a few of the 140g Barnes TTSX, jumping .050 from the lands.
Rem brass, Rem 9 1/2
65-66g of the IMR 4350
3200 fps
tiny groups
If a 7 Mag does not shoot this load, you need a new barrel, seems like a universal load, also works well with 140g ballistic tips and accubonds, KEY: touch the lands with the bullet, sort bullets for ogive lengths if necessary for the win.

67g of R#19
Win brass
Fed 215 match
3250 fps-3300 fps
Very tiny groups

Work up to these loads in your rifle as barrels and lot# of powder do vary, throw in a different brand of brass and you are in uncharted territory.

In the South, temperatures are somewhat stable as a rule, so the IMR will suffice. The H goes to Kansas where sitting in a ladder stand at -5* with a 15 mph wind is to be expected some years.

 

[Phil Rizzo]

H and IMR are two different animals. I think that you are over-igniting the powder with the Win mag primer, but accuracy in your rig tells all.

I shot quite a few of the 140g Barnes TTSX, jumping .050 from the lands.
Rem brass, Rem 9 1/2
65-66g of the IMR 4350
3200 fps
tiny groups
If a 7 Mag does not shoot this load, you need a new barrel, seems like a universal load, also works well with 140g ballistic tips and accubonds, KEY: touch the lands with the bullet, sort bullets for ogive lengths if necessary for the win.

67g of R#19
Win brass
Fed 215 match
3250 fps-3300 fps
Very tiny groups

Work up to these loads in your rifle as barrels and lot# of powder do vary, throw in a different brand of brass and you are in uncharted territory.

In the South, temperatures are somewhat stable as a rule, so the IMR will suffice. The H goes to Kansas where sitting in a ladder stand at -5* with a 15 mph wind is to be expected some years.

I've seen 67-69grs of IMR 4831 work in several 7RM rifles with 140 Nosler's also. And they were seated from touching to .010 off. Back before I payed attention to temp stability…

 

[VinceMule]

R#19 and IMR 4831 are kiss'en cousins as you well know, Phil.

 

[asd9055]

H and IMR are two different animals. I think that you are over-igniting the powder with the Win mag primer, but accuracy in your rig tells all.

I shot quite a few of the 140g Barnes TTSX, jumping .050 from the lands.
Rem brass, Rem 9 1/2
65-66g of the IMR 4350
3200 fps
tiny groups
If a 7 Mag does not shoot this load, you need a new barrel, seems like a universal load, also works well with 140g ballistic tips and accubonds, KEY: touch the lands with the bullet, sort bullets for ogive lengths if necessary for the win.

67g of R#19
Win brass
Fed 215 match
3250 fps-3300 fps
Very tiny groups

Work up to these loads in your rifle as barrels and lot# of powder do vary, throw in a different brand of brass and you are in uncharted territory.

In the South, temperatures are somewhat stable as a rule, so the IMR will suffice. The H goes to Kansas where sitting in a ladder stand at -5* with a 15 mph wind is to be expected some years.

Vince, are those the Rem 9 1/2 Large Rifle? Its interesting but back in the day, my old now retired Marck V, 300WBY, liked IMR4350 with Rem 9 1/2 (NON Mag).

 

[cohunt]

I originally used rl22 for the 140-160 class bullets in my 7rm-- then I tried rl23 and I'm hooked
With rl23 i shoot the 162eld at 3100 and the 145hht at 3280

 

[VinceMule]

Yeppers, the standard 9 1/2!

 

[VinceMule]

R#23 is a fantasy around where I live as are many Alliant powders.

 

[cohunt]

Rl22 was almost as good as 23, but its not as temp stable.

 

[VinceMule]

R#23 is just a rumor around here. I have seen R#23 in pictures.

 

[PC Python]

I have great luck with RL23 in my 7 Mag.

 

[Mike6158]

H and IMR are two different animals. I think that you are over-igniting the powder with the Win mag primer, but accuracy in your rig tells all.

When I first read this I thought... but it's a magnum cartridge. Then I thought, let's test that theory. Let me tell you, it ain't no theory, it's fact. I started off by loading the same powder test again but I don't recall why I did that. Some neuron fired and that's what I did. As it came closer to range day the bold faced text above kept haunting me. I learned a valuable lesson today. Enough bs... check these graphs out.

This is the H4350 retest. It looks just like the first test I did only this time I shot it at 200 yards and the horrible groups from the first test were amplified. Group 8 and 9 each had an ok group but I doubt if it would repeat.

This is the H4350 test with Federal Large Rifle Match primers (not magnum). I shot this test at 100 yards. 5 groups at or under 1/2m.

 

[asd9055]

When I first read this I thought... but it's a magnum cartridge. Then I thought, let's test that theory. Let me tell you, it ain't no theory, it's fact. I started off by loading the same powder test again but I don't recall why I did that. Some neuron fired and that's what I did. As it came closer to range day the bold faced text above kept haunting me. I learned a valuable lesson today. Enough bs... check these graphs out.

This is the H4350 retest. It looks just like the first test I did only this time I shot it at 200 yards and the horrible groups from the first test were amplified. Group 8 and 9 each had an ok group but I doubt if it would repeat.

View attachment 487421

This is the H4350 test with Federal Large Rifle Match primers (not magnum). I shot this test at 100 yards. 5 groups at or under 1/2m.

View attachment 487424

I have two different loads for 300WBY, two different bullets and powders, that both work best with LR primers, not magnums.

 

[VinceMule]

Magnum primers increase in intensity, lowest to hottest in my experience

9 1/2m
CCI 250
Fed 215
Winchester magnum, and let me say that R#25 loves this primer in a 7 Rem mag

A friend took pictures of primers as they were igniting and published those pictures in Precision Shooting magazine years ago, it is unbelievable just how different the flames are and the types of particles in the flames!