300 WinMag Retumbo or H1000

[bigngreen]

Your first H1000 groups look great, but double grouping which usually indicates something moving or settling either in the optic to receiver fit or receiver to stock fit. I have seen a number of poorly installed brakes also cause stupid big groups, it's worth shooting a group or two with out it.
The way it shot small at first with H1000 I would definitely hold out some hope.

 

[BrettS]

For what its worth. If you brought me that rifle here is what I would do.

1: Pull the rail. If I saw signs of movement on the underside I would pin it or replace it with a NF rail. Either way it would get bedded to the receiver.

2: I would clean the heck out of the barrel with Bore Tech Eliminator.

3: I would load up 6 rounds with 76.5 gr of H-1000 and a Fed 215 (first Choice) or a CCI 250 if I did not have the Fed 215. Then seat the 215 Bergers just touching the lands to start. Shoot two (3 shot) groups allowing cooling between. 9 times out of 10 this will be a sub moa deal. If not I would go up or down 1 gr of powder. But if it shoots a 2" group I would have to believe the rifle (most likely barrel) has a problem.

Hope this helps.

Jeff

Thanks Jeff, I just organized a NF rail and I will bed it to the receiver.
Got the Bore Tech and will give the barrel a good scrub.
Just got some Fed 215's so will do some loads tonight.

Will let you know how it goes.

 

[BrettS]

Your first H1000 groups look great, but double grouping which usually indicates something moving or settling either in the optic to receiver fit or receiver to stock fit. I have seen a number of poorly installed brakes also cause stupid big groups, it's worth shooting a group or two with out it.
The way it shot small at first with H1000 I would definitely hold out some hope.

Thanks for the suggestions, I will bed the rail as advised and see if there is improvement.
Will definitely shoot a couple of groups without the brake and see what happens.

 

[BrettS]

Bedded my rail to the receiver, also did some loads using 76.5gns of H1000 and 215 Bergers touching the lands. Went and shot a few groups today, wish I could say the results were better but would have to say not much has changed.

Will try some 210 Bergers, but starting to think about getting it re barreled and the action trued.

 

[oldno7]

Before you try another powder/bullet comb, adjust your OAL.

I'd start at 10 thousandths(.01) off lans and go to 50(.05).

You should be happy somewhere in there.

 

[BEEMAN]

I agree with trying different COAL. We have found in a few different rifles that the 215's like 30 thou off the lands.

 

[aebhunter]

I have a Sendero with similar things done to it. APS brake, bedded, timney trigger. I am running an Athlon Cronus scope. I also have two friends who are running 700 tactical platforms (factory) and know of two others with Sendero's as well. All .300 win mag. Every single one of those guns shoots sub MOA at 100-1000. Every gun is also using some variation of H-1000, Fed 215 primers, and either Berger 215's or Hornady 212 ELD-x. My recipe is:

78.5g H1000
Fed 215 primers
Berger 215 Target Hybrid
3.906 Base to Ogive measured with comparator
2940 FPS

My gun also shoots considerably better with about 10-20 rounds down range after a cleaning. I clean randomly every 50-100 shots. Have you tried shooting it without the brake? One more thing to eliminate I guess.

 

[Broz]

I really hate to say this, and I hope seating depth changes prove to be promising. But if it does not shoot better with the brake off I would be ordering a barrel.

Jeff

 

[BrettS]

I really hate to say this, and I hope seating depth changes prove to be promising. But if it does not shoot better with the brake off I would be ordering a barrel.

Jeff

My previous loads were 20 thou off the lands and shot the rifle prior to fitting the brake and groups were the same as I'm getting now, I could even say it's been really consistant.

 

[bigngreen]

Please don't take this wrong but how solid is your shooting system and your technique, the reason I ask is your first groups is totally horizontal with zero vertical which I would see some hope in, then the next two groups are total vertical with low horizontal. This could very, very easily be a rear rest or a shooter issue but I don't know you so it's hard to tell.
Honestly if I were shooting this gun, I know when I go through and set one up it's solid in the stock, rail and optic and I know my weekness in shooting and know when I'm on, if I had these groups for 30 rounds the barrel would be gone!!

 

[Tumbleweed]

Lots of buzz about RL 26 being faster too. But I guess I am stuck in the rut with H-1000. Over the years it has alway been my go to for the 300 win mag with heavy bullets. Plus I get over 3K from a 215 in a 28". I am happy with that.

Jeff

Jeff, FWIW I have been working on a load in a Remington 721 300WM with a factory 26" barrel. I can tell you that RL26 is significantly faster than H1000 at least in the two factory 26" 300WM's I've loaded for. In those, I hit the wall with H1000 at about 2850fps and they would not shoot there. In load development with RL26 I easily reached over 3000fps before I hit excessive pressure. This was with Rem brass, CCI250's and 76.5 grains RL26. I have not tuned a load yet as I'm in the process of troubleshooting some equipment problems.. So it's too soon to know whether it will shoot accurately at these speeds.