Check out my 1st LR Gun - 280 AI!

[rcdinaz]

Awesome gun! gun)

I agree with WildRose try the H1000. I have been using Retumbo in a 300RUM and 7mm Dakota this summer and just tried H1000 in those guns and the ES and groups both shrunk. I spent quite a few days at the range this summer when it was 112 - 118 and the H1000 was more stable than the Retumbo, in some powder charges the ES was very large with Retumbo in the heat.

Another thing is the heat you described should actually make the velocities higher so be sure to shoot when it is cooler. You did not mention if you saw any signs of pressure but if you haven't seen any signs I dont see why you cant test up to the max load, the pressures would actually be lower in the high heat. In the 300 RUM the difference from some of my range days to shooting in the mountains where it is cooler and there is elevation had a MV decrease as much as ~10%. Just some things to think about.

 

[jeffwhip]

Thanks for the input. So far I have tried H-4831, RE-22, H-1000 & Retumbo and haven't been able to find a load that beats the first 3 shots fired out of the gun. While at the gun range yesterday, I tried 63.0 G of Retumbo and shot 3-shot groups with the bullet depth anywhere from being jammed into the lands to .050 off the lands. The best 3 shot group I got 1/2". I got very good velocity out of this load but it left me scratching my head. In almost all of my tests, shot 2 was 1 1/2" from shot number 1 but then shot #3 cut the hole of shot #1.

The good news is that the weather has significantly cooled here in Phoenix, and I'm on vacation next week so I plan on hitting the range hard. I'll try to post some more pictures as I seek advice.

 

[jpeaston]

I just built a similar rifle, if your barrel is 1-9, we have the EXACT same barrel.

I pretty much only use 4831sc because of similiar temps here in the Central Valley of CA. I stopped at 63 g with nosler brass and Fed 210m primers, 140 ttsx bullets, with no signs of pressure at 92 degrees and 3090 fps. I laddered 59.5 to 62.5 from 300 yards and they all came in touching (in steel) with the exception of the 60 g load jumped high about 2 inches.

In my particular rifle it seemed the more powder you put in it the smaller the groups got. The day I laddered I had a pre-determined stopping point of 63 grains (if I got there safely) and had 3 rounds loaded. After the ladder I backed up to 400 yards and in some mild mirage shot a three shot group that went about 1/4 moa vertical and a little over half moa wide, and just called it good. load is 50 off lands and 13 fps spread over three shots.

Side note: Rifle has shot 150 sst, 150 smk, and 140 ttsx under half moa at 200 yards with 59 grains.

 

[jpeaston]

ladder at 300 yards and 3 shot at 400 yards. Pics came in sideways for some reason, put your head on your left shoulder when looking at them, lol.

 

[jpeaston]

5 shot 200 yards.

 

[WildRose]

5 shot 200 yards.

Houston we have a definite shooter here... .


Nice

 

[fmajor]

Yep - that's some outstanding shooting.

~Jeffwhip - your rifle is saaaa-weet!!!! WOW - what a nice shootin' iron! ALso, i like the reference folders on your shelf - OT: Prophets, Gospels, etc. Reminds of Seminary and trying to keep 'relevant' notes on areas of Scripture.

Now, don't cause yer brother to stumble w/ the nice LR rig ya got there!!! Go 'ugly it up' w/ some hunting scars!!!!

 

[jeffwhip]

Jpeaston,

Yes, I do have the same barrel. I'm going to try some 180 G Bergers next week and see if they will pattern with H-1000 or Retumbo. I'll let you know what I find out.

 

[Limbic]

My 280AI GAP with Templar action. I run the 168VLD at 2750 fps. I will slow down to 2700 probably in the winter. Pretty slow but the accuracy is undeniable. It will get them close to 3ooo fps but I'm going to try something different and see how the lower node works for barrel life.
I can tell you that my shoulder likes it. Also I don't shoot much over 600y so at 2700 I have plenty of energy to kill a whitetail.

55g of 560, .030 off the lands

 

[jeffwhip]

Limbic,

Could you please tell me what primers you are using, Powder, Bullet seating depth etc. Thanks in advance!

 

[Limbic]

Ofcourse that is an above average group. It will shoot 3 shots in the .4's consistently.
168vld
55-55.3g of N560
210M
.030 off the lands. Ogive to rim is 3.740

I've gone the route of 168vld at 3000 fps and 180vld at 2950 with my old 7mag. Barrel lasted 1200 rounds. This is less overbore but I'm still going to drive it nice and easy