Cast in 15" Encore 450 Marlin???

[Vance in Ak]

I've tried two different companies hardcast bullets in this gun. One was a 365gr, the other a 420. Didn't try a lot of loads with either, but the loads I did try wouldn't stay under 5" @ 50 yds (scoped & a rest). 405gr Remingtons go into one big hole at the same distance.
I had hoped to shoot the cast & got great velocity (the 420s were doing 1850fps while still 1.5gr under max & no pressure signs). Both brands were sized .459. I may slow the 420s down to 1600 & see what happens.
Anyone having similar experiences in the Encore or any suggestions?

[Nazgul]

Are you talking about a rifle length barrel or the shorter pistol barrel?

I have a 15" Encore in 450 Marlin. I shoot the Ballisti-cast 420 gr FNGC with good results. Have been using AA2015. Have reached 1600 fps which is uncomfortable, keeping them to 1400 or so is much nicer. Accuracy is about 3" at 100 yards with a rest (2x scope).

[Johnch]

Have you checked the bore di. ?
The bullets you tryed may be to small

Is the barrel ported ?
I had real problems with my 45/70 Contender barrel with plain based bullets after I had it ported
It would shoot patterns not groups

While a GC bullet it still shot great groups

I later read that porting can mess up the base of a plain base bullet as the gas escapes thru the ports , it cuts the plain base

Not sure if it totaly true
But ................................. I found in my barrel, plain based bullets didn't shoot for (&%*(&% after I had the barrel ported

Johnch

[Vance in Ak]

Johnch.
I have not slugged the bore.
The barrel has the factory expansion chamber type brake.
Both of the bullets I tried were GC.

Nazgul, it is the 15" barrel. The 1800+ with the 420s was with RE7.
I tried both RE7 & H-322 with the 365s, with equeally poor results.
With the 405 Rem jacketed I'm using H-322.
droipping the speed with the cast may make the difference.

I'd really like to play with this barrel some more & get it shooting cast bullets nice.
When I bought it that was my intention.
I live in Alaska & like the idea of big heavy cast bullets that plow right thru big heavy critters.
I have no qualms about the Rem. jacketed bullet for black bear, & probably even moose, but I'm curious how it will hold up if I get a chance to smack a brown bear with it.
For right now I have a bear hunting trip coming up in just over a week & I'm running out of time to play with new loads.