270 Sherman Load data

[ramrod79]

Well I've decided to put another Sherman together in a LA I have a 338 barrel on way to house but after some looking I'm thinking a 270 Sherman will be a better fit for me shooting 170 EOL. That being said I have my barrel guy looking for a Bench #4 1-8.5 or 9 twist to finish at 26.
So I'm looking for load data for the 170eol I have a ton of N 570 that I would love to use up as its my go to in my 6.5 Sherman. Any info you 270 Sherman shooters have got the big heavies let me know. I was hoping for 3050 pushing the big pill.

 

[dok7mm]

Tag

 

[zr600]

On Ritch's site it says a 1:8 twist should be the best if you plan on 170 eol. I would get the 1..8 twist.

 

[ramrod79]

You bet I've saw that talked with a few gents that shoot them in 270WSM have good luck with 1-9 I'm gonna do a 1-8.5 should work good I hope.

 

[Idaho Trecker]

I have a 270 Sherman and SS both with 1:8 twist barrels that I shoot 170 el and 165 matrix from. My ss has a brux and Sherman has a lilja. My ss prefers matrix and the Sherman the Berger. I have been using 280 rem fireformed (norma) brass and mostly fed 210 gm primers. Cant remember for sure if I started a thread on 270 Sherman loads or not but a lot of my info can be found here https://www.longrangehunting.com/threads/270-sherman-build-completed.152046/
The first few pages are mostly my learning curve coming out from a few years ago as that was the first wildcat I had done with more steps to make than the AI's i have.
I have done testing with different primers as well as a bunch of powders including n570 which is what you said you have.
I actually did my primer testing with the n570 and it was eye opening. My best es had the worst groups and worst es had best group! I didnt follow up with seating depth since I went back to rl 26 and 33.
My Sherman has a 28" barrel and with my current load (rl 33)with the 170 I'm getting 3030 fps and at top end for capacity and pressure.
Also a thing to note is the super long throat on mine. I seat my bullets Really long which gives me a bit more capacity. Pretty sure if it wasnt fir the long throat and drop tube I would not be able to get enough rl 33 in to work.

I've just started to play with imr 8133 and ramshot LRT which might be next choices if I didnt have n570. H1000 imr 7977 retumbo rl 23 and 26 all will work too. Never did try rl 22 or 25 due to temp problems but they should work also.
Might be able to load some up before I go shoot with elkaholic in the morning and take out to kill a rock.

 

[ramrod79]

Awesome thanks I really hope with long throat I can use 570 right now I use 65.5 and still have room in my 65 Sherm TheN570 really works well with the 140 berg.

 

[Idaho Trecker]

Funny you use that charge because that's what I'm running with the 170 and getting 2980-3040 fps depending on primer in my testing.

 

[ramrod79]

It's older 570 stored proper and I have a newer jug that I have to drop 1.5 to ge same results. The new jug yields 3310and slight extractor marks.
Well at least I know I'll fit enough 570 in case.
The only issue I have right now is I'm a die hard benchmark fan and they only make 1-8.5 witch should be fine with 170s.

 

[ramrod79]

what are your guys thoughts on a 24 inch pipe would it be realistic to get 2950 with shorter pipe. I had thought of jumping to a #5 fluted finished at 24 little more rigid keeping my same gun weight.

 

[Idaho Trecker]

That might be pushing really hard to get 2950 with the 24" barrel. At 3030fps I'm right at the top end and you would need a really long throat to get some more capacity so at least have it throated for the 170. I'll have to find my notes but I think I completely topped out over 3100.
On another note Rich and I made it out this morning (after a hectic start, Rich's story) to do some shooting. I had enough time to load up a couple rounds for the 270 Sherman. It turned out way better than expected for the distance. Forgot to hold spin drift and calculate the extra drop from the deflection and put me .5 moa low and 1.5 moa right. Instead of measuring with reticle I just guessed and raised 1 moa and held the windage. The next shot landed good for wind and high. Last shot landed on the rock (approx. .8 moa tall x 1.5 wide). 1832 yards. Not much energy left at that point and almost subsonic but not quite. Still makes for a fun time!!!

So many decisions on which rifle to take for my awesome elk tag I drew this year but this is a solid contender!

 

[couesaddict]

I've got a 270 sherman with an 8 twist, 27" rock creek bbl shooting the 170's. Mine is also throated VERY long. I'm shooting 63.5 grns of RL26 at 3080fps. I played around with 570 early on but found a load with 26 and was able to get a good supply of it where 570 was extremely hard to come by at the time. I didn't have a drop tube and was having trouble with it pushing the bullets back out a little on me. I'd like to revisit it sometime but 26 is treating me very well.

 

[ramrod79]

That's good to know but I have the same issue up here cannot get 26 but have 10lbs of 570 squirrelled away. Just wondering how the temp swings with 26 will work I shoot all year from late season elm at -25 c to plus 25c.
Idaho that's some awesome shooting wow 1832 yards
Well I have almost come to a decision on a barrel will be either a Hells Canyon CF #5 at 26 or a carbon 6 lightweight CF at 26 the only thing is I cannot find any info on the Carbon 6 but I did have a McGowen on a lightweight 260 that shoe lights out. I'm leaning towards HC CF as they are more established. Any thoughts on the 2 barrels.

 

[couesaddict]

That's good to know but I have the same issue up here cannot get 26 but have 10lbs of 570 squirrelled away. Just wondering how the temp swings with 26 will work I shoot all year from late season elm at -25 c to plus 25c.
Idaho that's some awesome shooting wow 1832 yards
Well I have almost come to a decision on a barrel will be either a Hells Canyon CF #5 at 26 or a carbon 6 lightweight CF at 26 the only thing is I cannot find any info on the Carbon 6 but I did have a McGowen on a lightweight 260 that shoe lights out. I'm leaning towards HC CF as they are more established. Any thoughts on the 2 barrels.

As far as the temp swings, seems to be under .5fps/*. I'm in AZ and shoot from around 0*-100*. I keep my gun and ammo shaded when it's that hot but it's been very predictable. I'd bet 570 would be even more stable though and with a drop tube I'm sure you'd have no problem. Especially since you're already established with the 6.5. It'll most likely give you equal or better velocity than 26 too.

 

[ramrod79]

I'm guessing I can take a 6.5 brass buck up to 270 to make up a dummy round I'll just leave a spent primer in just to see what I can get in case.