My 6.5 Sherman rifle and load development thread

[ramrod79]

A bit of an update was out shooting today after some powder lot discrepancies and I'm back at 65,5 gr N570 with 140 Berger ,and brass still looking good. I did start culling my bullets though, and now I base to ogive measure for best constancy as I found some really out of ball park.
Results were a 2" group at 600yards repeated for verification about a 5-8 min cool down between shooting.
I have to look in book but getting close to 500 rounds and no throat erosion.
This load prints a .75" group or better at 200 yards ( less than 1/2 min) as well 3255 was chrono speed.

 

[BEEMAN]

Think I may of asked this before. What type of brass are you using? I was maxed out at 64 gr of N570 with a 140 Berger and Nosler brass. Was very fast at 3339 fps. I ended up backing it off a grain to save brass. The brass actually wasn't to bad after 5 firings.

 

[ramrod79]

I'm using Norma brass same 50 I started with when rifle was new. I may pick up more very soon just in case. Very good brass for the abuse it takes.

 

[elkaholic]

Those are some pretty darn good results!

 

[dok7mm]

A bit of an update was out shooting today after some powder lot discrepancies and I'm back at 65,5 gr N570 with 140 Berger ,and brass still looking good. I did start culling my bullets though, and now I base to ogive measure for best constancy as I found some really out of ball park.
Results were a 2" group at 600yards repeated for verification about a 5-8 min cool down between shooting.
I have to look in book but getting close to 500 rounds and no throat erosion.
This load prints a .75" group or better at 200 yards ( less than 1/2 min) as well 3255 was chrono speed.


View attachment 102610 View attachment 102609
View attachment 102611

Thanks for sharing your info, I may have to revisit the N-570. My Retumbo load maxed out @ 3,200 fps, but 3,150 was very accurate. Congrats on those groups, some good reloading also.

 

[tim_w]

Ramrod79,


On that second group what do you think the cause of the vertical dispersion was? If you ran a chrony were the velocities ES/SD high?

They are both great groups @ 1/3 moa but they have a very different dispersion. It may just be they are 3 rd groups. But grp 1 has what 1/2-1/3" vertical where group two has close to 2".

I have had weird winds and barrel whip do things like that where the movement is more than can be accounted for by vel spread hence my ?????

No matter that is a good load and great shooting.

I will be noting that load.
What is your barrel length?
OAL to ogive?
Jump?

 

[ramrod79]

I'm not sure I think it was me not letting gun cool enough or just me I was having hard time seeing that green tape with sun coming up I would have to look in my book but es and sd were not high.
On a good note I was shooting out to 800 at my 8 inch round steel a few days ago and I shot a 2 3/4 group.
Barrel is a 26 Bench
OAL is 3.415
50tho jump
I do have some 160 matrix To try just not sure if I'll stick with N or try Ret again.

 

[rockwallraider]

were you using norma 280 brass or 270 brass?

 

[Korhil78]

I use 280 brass in mine.

 

[ramrod79]

were you using norma 280 brass or 270 brass?

I used Norma 270 brass necked up to 280 the necked down to 6.5 giving me a false shoulder then fire formed using COW. I did try the 160 and they shot ok very good velocity but just could not get groups where I wanted so I went back to 140VLD. I with the 156 were around then to try.

 

[rockwallraider]

I am waiting on my 65 sherman to be built but have bought 270 norma cases. I used a mandrel and necked up to 30 caliber then put in the sherman sizing die and the included picture is what they looked like? look normal to you before firing forming?

 

[puttnpurr]

Tagging in

 

[ramrod79]

I'm not sure I would have went to a 30 cal then down to 6.5 the less brass movement the better and you don't need much of a false shoulder. That looks like a good false shoulder but you will need your rifle as you will need to try in your chamber as you will want a good crush fit for forming. If you go to much you won't get a good seat and brass will not form properly and not enough and bolt won't close you really need to have your rifle.
When I do mine I try each one in chamber as I neck down to ensure i get best crush fit not sure if that's totally needed just my process.
I did cheat once and just neck down 270 to 6.5 it worked but shoulder was a little to small for my liking so I just went back to neck up to 7mm with 280 die then run in Sherman die that was best results. I used 12 gr of DOT for forming worked well. Shoulders took one firing to get nice and sharp that I did when breaking barrel in then did load development.
There was so much good info on this cartridge and the guys on this forum were so helpful load development was super easy. You like this cartridge super fun.

 

[rockwallraider]

Got 30 cal from elk himself. We will see.