New 6.5 Idea

[elkaholic]

Wow, I must say that round turned out great with some real potential!

So this question is open to anyone with some experience to which powder might work best for pure accuracy without too much trial and error in a 6.5/300 WSM, since barrel life could be limited.

My current load is 65.0 grains of Retumbo behind a Sierra 140 gr. GK @ 2.400" ogive length. It shoots 3/8" groups @ 100 yards, but only at 2990 fps average 20' from the muzzle w/ a 24.5" barrel. I was hoping this would keep it shooting great for a longer period of time?

I tired IMR 7828, 7828 SSC and H4831 during barrel break in with little luck. I'd like more speed but I don't want to give up anything in the accuracy department. I have a box of 140 gr. Matchkings I'm thinking of toying with, but I hate thinking of all the load development it might take to produce another better round.

I have enough magazine room that the 140 gr. Matchking's will seat with the Boat tail taper right at the neck/shoulder juncture in the case. So my hope is that it should shoot well if I can find the right powder. So any suggestions would be greatly appreciated.

Thanks

You might try some RL 17, especially since you only have a 24 1/2" barrel. Instead of 65 grains you would probably be closer to 55+. A good rule of thumb is every barrel with a given bore size will burn (X) pounds of powder in it's lifetime, so reducing the charge definitely helps....Rich

 

[elkaholic]

I looked up the post. You're right. RL 33 would be wayyyy too slow for this cartridge. It looks like and uber over bore powder too me.

I was planning on using it in my 30/375 S.I. so I did a little research and found it is even too slow for that case! It looks like the burning rate is close to the old H870 which was great in my RUM.......Rich

 

[MontanaRifleman]

I was planning on using it in my 30/375 S.I. so I did a little research and found it is even too slow for that case! It looks like the burning rate is close to the old H870 which was great in my RUM.......Rich

If it takes 102 gr under a 230 Berger in a 300 RUM, then it is probably only good for 230 grain bullets and above in the RUM. 100 gr of Retumbo in my RUM cases are about 100% capacity. It is advertized to be THE 338 Lapua powder for 250 gr bullets but that doesn't make sense. They need to come up with something in between 17 and 33. 33 would probably be great in a 7 RUM.

 

[IdahoCTD]

R-33 is pretty slow. I have to load 3 grains more then Retumbo in my 6.5-300wm to get the same pressure signs. I did pick up about 60-70fps though. I would think a 7STW on the low end of capacity in 7mm, .300RUM in .30Cal, and .338 LapuaAI/.338-.378 in .338 cal. to get the biggest (or any) gains.

 

[elkaholic]

Today I sat at the bench filling a fired but sized case with all the powders that might work in the BPX case. I built a wood dowel with a boat tail that pushed into the case to simulate a 140 Berger seated to the correct depth and then swirl charged with a long drop tube to get the max in the case. The results.

VV 160-- 50 gr.

IMR 4831-- 50.4 gr.

RL 19 ----- 51.3gr.

H 4831----- 51.2 gr.

RL 22 ------ 50.1gr.

RL 25 ------ 50 gr.

H 1000 ---- 51.3gr.

Retumbo -- 49.2 gr.

Quick load says that IMR 4831 and RL 19 are the only viable choices to get into the 3000 plus fps range. I suspect RL 22 would be a candidate also but the others are probably way to slow.

I guess It's time to hit the range with three more shot strings!!

Thanks for the quick load info Steve.---- RHB

I would try N560 if you like 160. The 560 has more energy with about the same burning rate. It usually gives higher velocities......Rich

 

[270 lefty]

270 lefty. thanks for the endorsement . I remember yours being the one with the bolt on the wrong side!!--- RHB

yes I'm one of the cursed. cant find a ball glove or a rifle with much more effort

 

[7mmRHB]

Rich, the VV n160 and 560 are too quick. They are quicker than RL 17 so I probably won't try them. I'm hoping one of the 4831s will get us what we're looking for. I'm still going to try RL 22 because of all the times it's worked in cases that it probably shouldn't have. Thanks for your input. --- RHB

 

[elkaholic]

Rich, the VV n160 and 560 are too quick. They are quicker than RL 17 so I probably won't try them. I'm hoping one of the 4831s will get us what we're looking for. I'm still going to try RL 22 because of all the times it's worked in cases that it probably shouldn't have. Thanks for your input. --- RHB

I haven't found that to be true in the rifles I load for. Sometimes the cartridge will determine the burning rate, as I'm sure you already know. N560 is "definitely" slower and is closer to N165 which you might also try, but the N560 will likely give better velocity.......Rich

 

[7mmRHB]

You're right Rich, N160 is just barely slower than RL 17. It's just not enough to make me think it would be the right powder. I've had no experience with N560 so I won't speculate on that.

Between bad weather and work I'm having a hard time getting the next tests done. I'll try to get out in the next few days and report the results, good or bad . ---- RHB

 

[liltank]

Don't forget to try the Superformance powder also.

 

[7mmRHB]

Tank, I've never used Superformance but have seen lots of articles about it. I've never seen a low SD or ES reported ever. If you have info proving other wise I would be interested in seeing it.

Thanks ---- RHB

 

[65WSM]

My experience is with a 9 twist 26 inch barrel on a short action "Virginia" Model 70 in 6.5-284. I shoot the 130 Bergers so I can fit them in my magizine (3.5 inches).

I found that 68.8 to 69.2 gr of Vihtavouri N-560 gave me 3280 fps. I can only get about 20 more fps with the larger 6.5 WSM case and several more grains of Retumbo or Magnum as the powder.

Lets see several of your chronograph strings. What powder and charges are you using?

 

[elkaholic]

My experience is with a 9 twist 26 inch barrel on a short action "Virginia" Model 70 in 6.5-284. I shoot the 130 Bergers so I can fit them in my magizine (3.5 inches).

I found that 68.8 to 69.2 gr of Vihtavouri N-560 gave me 3280 fps. I can only get about 20 more fps with the larger 6.5 WSM case and several more grains of Retumbo or Magnum as the powder.

Lets see several of your chronograph strings. What powder and charges are you using?

+1 on the N560.......Rich

 

[MontanaRifleman]

My experience is with a 9 twist 26 inch barrel on a short action "Virginia" Model 70 in 6.5-284. I shoot the 130 Bergers so I can fit them in my magizine (3.5 inches).

I found that 68.8 to 69.2 gr of Vihtavouri N-560 gave me 3280 fps. I can only get about 20 more fps with the larger 6.5 WSM case and several more grains of Retumbo or Magnum as the powder.

Lets see several of your chronograph strings. What powder and charges are you using?

Did you try RL17 in the WSM?