260 Remington load development

[SwampSniper]

So built this rifle last year and I think I finally found a good load for it. It's been quite a head scratcher. Best load so far is 41gr rl 17 140 Berger vid and cci 200 primer. Tried like hell with 140 amaxes but never got under 1/2 moa. The Berger load shoots .1-.2 on every trial so far @ 2.88 coal in virgin lapua brass. Not sure about Es sd but shot a group at 500 yards with about 1" vertical deviation so I'm guessing it's good enough. Chronographed one at 2840. Not smokin I know but definately acceptable.
Rifle is a Remington sa with a 26" rock creek and a5 stock. Nxs 5.5-22x50 on top
Seekins dbm and timney 510

 

[SwampSniper]

.135 3 shots @100 140 vld

 

[SwampSniper]

Forgot to put my question in the first post lol. I have about 600 140 amax and haven't had much luck finding a load. Any recommendations on jump/jam? I still have 5-600 140 vlds but got the amax on sale almost half the price so I'm really hoping to find a good load with them

 

[Greyfox]

I have done work with the 140Amax, Berger 140VLD, and 142SMK. The best, .25MOA with the AMax was .025" off the lands with 45 gr of H4831sc, 210M, Lapua brass. Velocity was 2800FPS. In do get better accuracy(<.25MOA) with the Berger and SMK though.

 

[SwampSniper]

I have done work with the 140Amax, Berger 140VLD, and 142SMK. The best, .25MOA with the AMax was .025" off the lands with 45 gr of H4831sc, 210M, Lapua brass. Velocity was 2800FPS. In do get better accuracy(<.25MOA) with the Berger and SMK though.

Thanks, I'll have to try some 4831 or a different primer maybe. I've tried it in 15 thou increments from 50 thou off to 10 jammed with decent results about 20 off but just not what I know this rifle is capable of with other bullets. I've been wanting to try 4350 or 4831 but I'm out and it's hard to find around here that's why I settled on rl17 I'm just worried the temp sensitivity of the rl17 may be more than I want

 

[ta406]

I was in the same boat as you. I tried like heck to get the 140 amax to shoot in my 260. No matter what seating depth, powders (H4350 and H4831sc), or primer I tried, they just wouldn't shoot. I gave up and went to the 140 SMK. My best group with the amax at 200 yards was 2". After only a couple different loads with the 140 SMK, my best group was .3 at 200 yards, and have repeated it regularly. There may still be some room for improvement but I'm more than happy with that. I have seen some impressive groups like yours with the Bergers so I'm gonna give those a try next. Now I have a couple hundred amax's to give to my 6.5 creedmoor buddy.

 

[Deleted member 46119]

Forgot to put my question in the first post lol. I have about 600 140 amax and haven't had much luck finding a load. Any recommendations on jump/jam? I still have 5-600 140 vlds but got the amax on sale almost half the price so I'm really hoping to find a good load with them

I run my 140 A-Max at -.005 over H4350. Yes it's in the .1s. 2.985 COAL.

 

[Canadian Bushman]

I always struggle to repeat a loads performance when its worked up with virgin brass. Id consider taking careful measurments of the virgin brass and trying to repeat those dimensions with a FL sizing die.

Hopefully your load is tolerant of small changes, but if i it were my gun that was shooting that well, id be hell bent on trying to keep it that way.

 

[SwampSniper]

I always struggle to repeat a loads performance when its worked up with virgin brass. Id consider taking careful measurments of the virgin brass and trying to repeat those dimensions with a FL sizing die.

Hopefully your load is tolerant of small changes, but if i it were my gun that was shooting that well, id be hell bent on trying to keep it that way.

Glad you brought that up it was a concern i had. Once this lot of brass has all been fired i figured id try the same load with fl sized and neck sized brass as well to see what happens. If it keeps shooting like this ill be happy to say the least! Long as it stays close to half inch at 200 ill be happy as i think thats probably as good as im capable of in most conditions anyhow

 

[Canadian Bushman]

One of the big contributing factors for me is the dia. of the case near the head. I believe this part of the case is thick, hard, and absorbs the most energy. Controlling this dia., along with headspace, will yeild consistent MV from batch to batch. Different FL dies wont always yeild identical diameters on this location of the case.

Also you may consider annealing often. I dont find that the neck hardness affects a load too much but it would definitely help you maintain consistent neck tension. Especially if the neck is being expanded more than .005-.007" each firing.

Dont mean to try to tell you how to handle your reloading, you obviously know what youre doing, but having a rifle consistently shoot 1/4 moa is a pretty special thing and i just wanna help you keep it there.

 

[SwampSniper]

Loaded up 20 more the other day, so one day this week ima take her out to 1000 and see how she does

 

[rem338um]

If I had a 1/4 moa gun and load I would throw the rest away and call it good! Great shooting!

 

[Metzger]

Nice groups. Who did the trueing on the 700?

 

[SwampSniper]

Nice groups. Who did the trueing on the 700?

Bob racine in lake havasu arizona built this rifle for me. You can check him out online. Google southwest precision customs. Super nice guy and easy to work with. Rifle shot 1/4 groups at 100 with two different types of factory anmo right out of the gate. Long range performance wasnt as good because of es/sd but still close to 1 moa at 1000. Now that ive got a decent load for it ill be stretching it out more