Short barrel 6.5 - How about a RPM?

[orchemo]

Winter rains are here, so cabin fever leads to what is next?
Been shooting the 30-06's and 338 Federal the last couple weeks.

Thinking about another 6.5 though. Already have a 6.5 CM and long throated 6.5-284. Both shoot great.

My thought for a short barrel, suppressor ready 6.5 is......

I have a couple Tikka actions around. Grab a 6.5 CM Tikka barrel, rechamber to 6.5 RPM, cut to 18 inches to host a suppressor.

Rationale for the 6.5 RPM is
1. Gives me great velocity in standard long action (30-06 based), even when cutting to 18 inches.
2. Can use a standard 30-06 bolt face.
3. Barrel - ask my local gunsmith to re chamber a factory Tikka barrel which is already 1:8 twist. Take off barrels are relatively cheap and Tikka barrel always shoot well.

Cons: finding right powder to maximize the velocity in an 18 barrel, another cartridge to load for.

Thoughts?

 

[xphunter]

There are no cons, other than you will have reduced MV compared to longer barrels
Just use the same powders you would normally use for a standard rifle length barrel of 24-26 inches.
Let's say the MV with 140's is 3000 fps with a 26" barrel.
I would guess 25 to maybe 30 fps loss per inch.
8x25=200, So 2800 fps.
On of the AB loads 140 grain loads had a MV of 3075, so possibly 2875.

With 17 inch 6.5-284's, I have had 140's reloads to 2775, and a tad higher with sustained shooting, so I would expect the upper 28's when loading with a 18" 6.5 RPM

 

[clearwater]

Cons: "another cartridge to load for. "

I think you meant Pros: