Powder Test 7mm Rem Mag

[Mike6158]

I've been running tests on Powder and 150gr Barnes TTSX on my 7mm Rem Mag. The first test was with H1000. The powder test started with .3 grain increments, found a node where with a decent ES, picked one to fine powder test (.1gr increments), picked one from that test, went to seating depth test, and then picked one from those. I wasn't thrilled with what I got from that testing so I went to H4350. Group 4 has a false shot in it. I forgot to disarm the LabRadar before I closed the bolt and the LabRadar trigger I'm using recorded BS. The 2nd round is intriguing but that big fat ES 10-13-9 range at 3,000 fps is a gem. I didn't get anything that good with H1000. Temps on the day I shot were pretty steady at 100 deg F so I'll have to check it later this fall / winter when the temps are a lot cooler down here in TX. 85-90 with no chance of snow. Unless we globally warm down to freezing sometime.

 

[Mike6158]

I took the bad datapoint out and the plot is a little more useful.

 

[M1A1ABRAMS]

I took the bad datapoint out and the plot is a little more useful.

View attachment 481729

I was under the impression as a New reloader that H4350 & IMR 4350 were different ? I thought the IMR was a little more temp sensitive ? Is this not correct ? And is there a big difference from older IMR 4350 as to the newer lots ? I have a few pounds of each but have yet to test any of it.

 

[Mike6158]

I was under the impression as a New reloader that H4350 & IMR 4350 were different ? I thought the IMR was a little more temp sensitive ? Is this not correct ? And is there a big difference from older IMR 4350 as to the newer lots ? I have a few pounds of each but have yet to test any of it.

I'm not sure. I'm going to check my burn rate chart and see how much difference there is. It very well may be. I bought the 8# jug of IMR 4350 that I have many "bad presidents" ago. I wish I would have put the H1000 test data in Chronoplotter for a side by side comparison. I "think" I found the LabRadar series for my H1000 fine powder test. When I look at it in Chronoplotter it looks good but the IMR 4350 looks slightly better. The low ES range is wider. That could be from testing in constant 100 degree temps vs the temp swings from mid morning to afternoon that the H1000 test was run in.

I've gone through 200 bullets and primers testing a hunting bullet for the last couple of months. :/ I loaded the last of what I had (oops) and had to order some more so I can finish the fine powder test. I'll finish up the Barnes TTSX test and switch to 168gr VLD's over the next couple of weeks. I'm pretty sure the VLD's will out perform the Barnes but I guess we'll see.

 

[Mike6158]

153 / 154. As far as burn rate goes they are essentially the same. Typically we don't get big swings in temperature here on the Gulf Coast of TX. 30 - 100 vs sub zero to 100 in NW New Mexico (for instance).

Most of us here in TX would be adamant that jacket weather starts at 50 degrees because that's when water freezes in Texas

 

[Varmint Hunter]

I bought some IMR 4350 when I couldn't get H4350 for some time. Since it was just sitting there, I decided to use it in a rifle that I just rebarreled in 6.5 Creed. I used H4350 data and got almost exactly the same speed predicted for H4350. The two powders "seem" interchangeable.

 

[M1A1ABRAMS]

I bought some IMR 4350 when I couldn't get H4350 for some time. Since it was just sitting there, I decided to use it in a rifle that I just rebarreled in 6.5 Creed. I used H4350 data and got almost exactly the same speed predicted for H4350. The two powders "seem" interchangeable.

Do you remember when you tested ? Was it hot out ? I read a thread where someone said IMR was temp sensitive. This is what I was concerned with.

 

[VinceMule]

R#25 with Win Mag primers, gets you right at 3200 fps on a 26" barrel with 150g Nosler Ballistic tips and 154g Hornady Sp, Rem brass, SD less than 10 fps. The faster you shoot it, the tighter the groups, usually in the .300 range for three-shot groups that repeat. We seat the bullets to within .005 of the lands, groups start to open up jumping more than that amount. 150g Nosler ballistic tips are tougher than you would ever think, and the 154g Hornady sp will shoot holes through both shoulders on large hogs, rated an elk bullet.

I shoot the 154g Hornady SST with IMR 4350, 62.5 63.5g

Work up your load in 70-85 degrees, I never had a problem in Winter. I have seen tweaked stock Rem 700s shoot bug holes with the R25 load, and the Win Mag primers seal the deal on extremely low SD and Accuracy.

 

[Mike6158]

Do you remember when you tested ? Was it hot out ? I read a thread where someone said IMR was temp sensitive. This is what I was concerned with.

100 degrees on the money. It started in the 80's that morning but before noon it was 100 and it stayed that way.

 

[john k]

I was under the impression as a New reloader that H4350 & IMR 4350 were different ? I thought the IMR was a little more temp sensitive ? Is this not correct ? And is there a big difference from older IMR 4350 as to the newer lots ? I have a few pounds of each but have yet to test any of it.

IMR4350 is very temp sensitive compared to H4350. I get very good accuracy with IMR4350 but the fps is considerably slower if that matters to your desires. Agree with Vince Mule when to work up your loads.

 

[MagnumManiac]

I can tell you IMR 4350 is faster than H4350, and H4350 is an Extreme powder that is virtually temp stable.
I would be cautious using H4350 data for IMR4350 loading.

Cheers.

 

[MagnumManiac]

IMR4350 is very temp sensitive compared to H4350. I get very good accuracy with IMR4350 but the fps is considerably slower if that matters to your desires. Agree with Vince Mule when to work up your loads.

This is false, you have swapped the 2 for temp stability/instability.

Cheers.

 

[john k]

This is false, you have swapped the 2 for temp stability/instability.

Cheers.

Not false, just a little different wording. Either way same outcome.

 

[john k]

I can tell you IMR 4350 is faster than H4350, and H4350 is an Extreme powder that is virtually temp stable.
I would be cautious using H4350 data for IMR4350 loading.

Cheers.

In my 3 cartridges, it's the opposite but I totally agree with you being cautious interchanging data between them. I'm a fan of the IMR4350 so no hiding my age. Thanks