Substitute Powder Based on Burn Rates?

[waynewjw]

Can one use a powder with a burn rate that is either one above or below on the burn rate reloading scale???

Example: a buddy wants me to load .243 caliber 100 & 105 grain bullets with IMR4064? Lymans 49th Edition doesn't show 4064 for either of these two grains. A couple of year back he had another fellow from his work make some loads up using IMR4064 (this guy has been reloading for many years compared to me) and had a number of reloading books to refer to. This gave him some great groups and he now wants to repeat - the guy from work has moved and he can't find him to get the recipe from him.

The Lee Modern Reloading manual shows IMR4064 for the 100 grain bullet as 33 to 36.5 grains of powder, but no data for the 105 grain bullets and I just got some 107 grainers which we'd both like to try.

So the question is, based on burn rate of 4064, N135, VihtaVuori is faster burning, and Varget is slower. Varget is listed in one of the two manuals as a load for the 105 and 107 grain bullets.

My question is - can I use IMR4064 for the 105/107 grain loads but use the powder min & max load range for Varget, which is one down the scale and slower burning. In the case of the 105's - 29.7-33.0 of Varget, and the 107's - 31.0-33.0?

Is this logical and a safe way to approach this issue?

 

[joe-nwt]

http://stevespages.com/243_2_105.html

 

[FLHTCUI]

Ummm these recipes are not your Moms Bridge Party Saturday nights specials.
Go to the IMR site and see what you find there.
Just cause Lymans doesnt/didnt research itmeans your friends load is safe to use based on similar burn rates.
I'm just saying I would use some due diligence before trying an unproven load in my gun in my hands a couple inches from my face.
Your Mileage will vary for sure.
Tight Groups,
Rob

Added for effect, use the varget web page for the answers to your question.

 

[Farlsincharge]

If IMR 4064 was the last powder left on earth I would start at 29 gr and go up looking for pressure.
Being that it is not I would use something better suited for the heavier pills like H1000. But that is just me being concerned with temp stability, velocity, and recoil.

What is his twist rate? Those 107's may not stabilize.

 

[Ganderite]

Your logic is correct. But I think 33 is a bit much.

The reason the 4064 is not shown for 100 gr - 243 is that it is too fast for that combination. But it might make a very accurate load at moderate velocity. no harm in trying.

Do you have factory or custom barrels? Standard twist won't even come close to stabilizing a 107 Sierra match bullet, if that is what you have.

Before making very many of these, I suggest you try a few and see if they make round holes.

The slower powders, like 4350, 4831 and H1000 are the powders to get more velocity with these long bullets. And you need the velocity to get the RPM to stabilize them.

 

[waynewjw]

Rifle Twists

So my rifle is a Savage 14 with 1:9.25 twist. My friends rifle is a Browning A-Bolt with he thinks a 1:10 twist. In may be a 1:9.

He was getting incredible accuracy with the 105 grain Speer's, IMR4064 at 33 grains and CCI -BR2 primers, hence my thought that the Browning could be a 1:9 twist. He's had it for about 8 years, and the fellow he bought it from had it, we think 5 years, so.....it's 13-15 years old, if anybody has a catalogue they might be able to confirm twist??