Seat'em deeper

[HeathSexton]

I have been messing around with Mrs. Picky, aka my .260 Remington. I think I really need to bed the action and things will get better. Anyways, I was running my OAL 3.283" with my Hornady Gauge with 44.8grs H414 and the 120NBT. This was just .002-.003" off the lands. I was getting good accuracy but it was just real picky. I started messing around and shot some Federal 120 NBT's and they shot great, I mean great. I reduced my OAL to their depth, which is about .050" deeper. My charge of 44.8grs H414 was hell on brass, I know I should have reduced and worked up but I didn't. 2 loads and I had leaking primer pockets and terrible accuracy. I dropped down to 43.5grs H414 and groups are great. I chronoed the load today also.

44.8grs H414 @ 3.283" = 2888fps
43.5grs H414 @ 3.236" = 2911fps

 

[FOTIS]

........... I chronoed the load today also.

44.8grs H414 @ 3.283" = 2888fps
43.5grs H414 @ 3.236" = 2911fps

Weird! :?

 

[Antelope_Sniper]

How many rounds per string?
What where the hi/low's and the SD's?

 

[DrMike]

Looks as if you are plateaued in your charge; the next stage is climbing the steep curve to catastrophic case failure. I've observed this, as pressure rises, but velocity does not follow suit. Remember that Federal likely is using a non-canister powder. Did you happen to chronograph the Federal load? It might give you a clue to what you should be looking for in terms of velocities.

 

[HeathSexton]

The 44.8grs load I only took the average of the 3 shots and that was awhile back, as in years. I did not record anything other than average. I remember that I thought A: it should have been faster and B: the spread was more than I liked.


The 43.5grs load was a 3 shot string, 2911fps average, high 2925fps, low 2902fps.

I did not write anything else down. I did chrono some Reminton 140gr Factory Core-Lokts 2487fps and 2499fps, I only had 2 rounds. Slow, Remington says 2750fps, from reading this 2500fps is very normal.


I do not have any more of the Federal loads left, they shot so good I shot them all. Federal lists them at 2950fps.


The way I came about the 44.8grs load, my gunsmith took the gun and did some work to it. I asked him to work up some loads as I did not have any equipment at the time. I pick up the rifle with 100 rounds of these loads, they always shot good and I finally worked through them. It was only when I started my own load development that this surfaced.