260 rem pressures

[Coldfinger]

I finally got into 6.5 diameter. Picked up a 260rem from member. Just wondering what pressure spikes I should be noticing. Right now I'm cutting the same hole during pressure testing. I started at 41 gns h4350 and am sitting on 44 gns now. Launching Berger 140 elite hunters. Lapua lrp brass CCI Br2 primers.
No bolt lift resistance at all. But I know customs can hide pressure.

 

[just_jon]

QL and GRT estimates 44 grains of H4350 at 69,878 and 68,925 psi, respectively. SAAMI max pressure is 60,191. QL and GRT data is based on a COAL of 2.8" and case capacity of 53.5 grains of H2O.

 

[lancetkenyon]

I don't see any visible signs that I would be worried about.

 

[Coldfinger]

QL and GRT estimates 44 grains of H4350 at 69,878 and 68,925 psi, respectively. SAAMI max pressure is 60,191. QL and GRT data is based on a COAL of 2.8" and case capacity of 53.5 grains of H2O.

It's jumping a country mile to get to magazine length feeding but still cuts holes. There might be something to this 6.5 craziness I've ignored all my life

 

[MagnumManiac]

I don't see any signs of excessive pressure, but I would expect Varget to give better performance, it did in my 260 before I went AI with it, then H4350 shines over everything else.
What COAL/CBTO are you running?
My rifle is a REM 700 VSSF II, so mag length is restricted.

Cheers.

 

[VinceMule]

44g with 140s are very popular among the 260 guys. 44.5-45.5 in the AI. Every chamber/barrel will be different

 

[ShtrRdy]

Primers look fine. Do you have a velocity measurement? That's another piece of information we can use to infer pressure.

 

[Coldfinger]

Primers look fine. Do you have a velocity measurement? That's another piece of information we can use to infer pressure.

Not yet it rained all day. Don't have a garmin crono yet.

 

[Coldfinger]

Primers look fine. Do you have a velocity measurement? That's another piece of information we can use to infer pressure.

Not yet it rained all day. Don't have a garmin crono yet

I don't see any signs of excessive pressure, but I would expect Varget to give better performance, it did in my 260 before I went AI with it, then H4350 shines over everything else.
What COAL/CBTO are you running?
My rifle is a REM 700 VSSF II, so mag length is restricted.

Cheers.

I don't see any signs of excessive pressure, but I would expect Varget to give better performance, it did in my 260 before I went AI with it, then H4350 shines over everything else.
What COAL/CBTO are you running?
My rifle is a REM 700 VSSF II, so mag length is restricted.

Cheers.

I'm at 2.90" but got to get a tad deeper to not bind in Accurate mags. It's a surgeon action and bottom metal.

 

[MagnumManiac]

I'm at 2.90" but got to get a tad deeper to not bind in Accurate mags. It's a surgeon action and bottom metal.

OK, you should be good, I'm a tad shorter than you, but the AI chamber hides pressure real well. I'm at 49g H4350, no pressure signs. When mine was standard 260, I maxed out at 42g H4350 with 150g BT. Mine is 30" 8" twist.

Cheers.

 

[Lionel Boyd Johnson]

When I'm developing loads for a hunting rifle that I want to be able to feed from the magazine, I start my OL length tests just short of the magazine length assuming that the chamber would allow longer seated bullets. That way, I only have to test for best OL length in one direction - shorter.

 

[Pootyng]

43-45 grains of N160 with 140 sst is what I hunted deer with until I switched to a Grendel. I think it was 2700 from a 26" Austrian Mauser. I don't remember the coal but there is no limit on that action for the 260.