Favorite 243 powders: 2018 edition

[therifleman556]

Hello all. I've been doing some searching on the interwebs for favorite powders for the 243 Winnie. While I realize this has been covered before I thought I would put some feelers out there to see what new powders are around to help boost this old 6.

A co-worker and I are rebarreling a pair of 243s with 24" 1-8 twist McGowan barrels. I know he likes to stick with the 95 grain and up pills (for target work and sub-200 yard deer). I would like to throw out some 70-87 class stuff for small critters and go with something 105-107 maybe 108 for LR plinking and general deer duty.

I see there is data for RL 26 with heavies, along with Magnum. Anyone tried them?

There seems to be even more options for the varmint weight pills.

I'd like to hear everyone's thoughts on the new powders available.

Thanks folks!

 

[lancetkenyon]

H4350 is what I will be using in my 6CM.

I have a few bullets to test.
95 TMK
105 HVLD
105 Hybrid
110 SMK
115 HVLD

 

[Deputy819]

I should have a custom .243 Winchester (1-9" Douglas Premium Grade barrel) back from my smith any day now and here's what I'll be trying with 87 gr Berger vld's:

1) H4350 93% case fill
2) IMR 4831 98% case fill
3) RE-19 98% case fill
4) IMR 7828 SSC 100% case fill
5) H4831 SC 101% case fill
6) RE 22 102% case fill

I've also got a pound of the IMR Enduron 4451 sitting around that I'll try just to see what happens. There doesn't seem to be a whole lot of in-depth "tried and true" load info for that one yet.

 

[just country]

morning, 4064, 4320, RL15, H414, W760, 4831all, justme gbot tum

 

[therifleman556]

Alliant claims just under 3100 with RL26 under a 105. I've got a pound sitting around so it's going to get tested. If it does what it did in my 7 RM I should easily get there or possibly more.

 

[logan197]

Still have about 500 of the old 105 gr Amax. Retumbo is my go to powder with them. Getting 3050 fps and 7 ES with that load. Running out of a Savage 1:9.25 twist. Stabilize just fine.

 

[slas]

I haven't found anything that shoots better than Varget in mine.....I usually shoot the 85 gr Sierra's.

 

[RockyMtnMT]

Rl16 full case with 70g Hammer Hunter gives 3750fps. Ran out of case before pressure. Single digit es 3/4" group at 200y. Factory Ruger.

Steve

 

[tim_w]

In the 243 N160, H1000, RL26 H/imr4350, H100V I lean to heavier bullets so take that into account.

rl26 and 4350 with the former getting top speed, the latter is a bit easier to dial in but can get both there.

I really like the Alliant Rl17,26,33 powders where they work for various cartridges.


If you do not mind a small bit of vel drop try N160. It is the coolest flame temp powder in that class and can significantly increase barrel life round count. A great load is 105 hybrid 0.020 off 42.6 gr. Depending on the bore and your freebore you may have to go up or down a grain or two 41-45 is the range depending. But there is a great node in there.

I pretty much have been shooting 105s for few yrs now when I shoot the 6mm. Its such an easy bullet to tune and shoot accuracy for its BC.

 

[ShtrRdy]

tim_w -- how do you measure flame temperature?

 

[therifleman556]

Great information folks. Much to consider and by all means, keep it coming.

Edit: I see Berger lists the 105 hybrid as needing a 7" twist. Anyone have experience running it in 8"?

 

[tim_w]

tim_w -- how do you measure flame temperature?

I certainly do not measure it. I think its flame temp but they list them in the detailed powder specs. It maybe "heat energy or temperature" I know its in QL. Its why double based or high energy powders tend to eat throats quickly relative to there burn rate compared to many single base powders. Its fairly common knowledge that H1000, N160 N165 have cooler burn temps.

Here is a link to except of research article in Industrial Engineering Chemistry Reference Book titled : "Burning Characteristics of Smokeless Powder I—Burning Temperature" https://pubs.acs.org/doi/abs/10.1021/ie50257a006 It was authored by Hercules Powder Research and Experimental Division almost 90 yrs ago. US Mil also did extensive studies on flame temp in relation to various powders and achieved vel for given chamber and port pressures. But I can not seem to find a link to that one right now and would have to dig thru my archives fo find my copy. Likely way more info than anyone is interested in. I am nott sure if it directly mirrors to energy content but I do not think so as shape size perforations or not all can have an effect along with the various chems and treatments they use today.

Then again I could be totally misinformed or full of sh!t after all its the net.

 

[brentc]

I tried Norma MRP on whim in a RPR 243 and it quickly became my powder of choice with 105 HVLDs and Hybrids.

 

[Lonewolf74]

RL16...it performs very well with bullets ranging from 58gr to 105gr no need for a different powder for different load applications.