"Cool", and reduced loads for the .260 Rem - Update in Post #4

[Khromo]

I cooked up some honest sub-1/2 MOA loads for my .260 Rem (Tikka Sporter, with a 20" barrel) using 142 grain Sierra MatchKings (SMK) and 38.8 grains of H4350, loaded 0.025" off the lands. I like the accuracy, but I am a little concerned about barrel life. I have no money, and if I am ever going to get that new Miata that I dream about, I have to figure out a way to milk a little more useful life out of the factory barrel.

It should be noted that the local ranges only stretch out to 300 yards. There is an almost-1,000 yard range up the road, but it is a miserable drive, and until I get that new Miata, I'm not shooting beyond 300 yards.

I got some Winchester 748, thinking that the advertised low burn temperature might keep the throat erosion down. I found that 36.9 grains of W748 gets at or near 1/2 MOA with the 142 grain SMK. Grabbing the barrel during a range session seemed to indicate that the barrel was not getting as hot as when I shot the H4350, but such a crude test is barely worth mentioning. Suffice it to say the results with the W748 were promising, not necessarily for life-and-death informal target shooting, but definitely good enough for position practice, introducing new guys to the sport, and plinking.

My next experiment was kind of intriguing. I have some 107 grain SMK's I bought during the panic, and I have some H4895 I bought to load some "youth loads".

https://www.hodgdon.com/

(Click on "Data", then click on "H4895 Reduced Rifle Loads" on the drop down menu.)

I decided to cook up some of these reduced loads using the 107 grain SMK's, figuring if they didn't shoot, it wouldn't be a big deal because I couldn't figure out anything else to do with the 107's. I think I bought them during the panic, and when I settled down and started checking the loading data, I saw that the comparatively large charges listed for the 107's would be cooking my throat a lot faster than I would with the 142's.

I started at 28.0 grains (69% of the max charge in Hodgdon's data) and loaded five rounds at 0.4 grain intervals up to 32.0 grains (79% of max).

Seating a little less than 0.264" into the neck, the bullets were still a whopping 0.110" off the lands! I decided I should consider doing a little more research before buying bullets in the future.

I took a shower, which doesn't have much to do with the subject, but I was a little proud of myself for doing it and I wanted to let everybody know about it, and then I drove to the range to shoot some 5 shot groups at 100 yards. I hung the targets diagonally, as I like to align the crosshairs on the points of the bulls, and these targets were printed wrong! Some stupid flathead printer! Tilt your head 45 degrees to the left to get the proper perspective.





Someday I will learn to shoot, but for now I kind of have to use a little Kentucky windage to get past the clunkers. Discounting the wild shots (I don't call them "fliers" anymore. From now on they are wild shots. My fault.), I think there might be something approaching an accuracy node around 30.4 to 30.8 grains. Those groups measured 0.43", and it was not due to the skill of the shooter. I had to make a pretty dramatic (1/2 MIL) elevation adjustment between those two groups. I suspect the lighter loads are shooting like a rainbow, but I don't know.

For a half-blind shooter with the shakes and a factory barrel, I think this load might be useful for the candy-*** Miata driver inside 300 yards. It's burning less powder than starting loads for heavier bullets, but I don't know how much, if any, impact that will have on barrel life. The better loads seem pretty accurate, and that's what I was trying to achieve, so I suppose I should go drink some Irish whiskey and shut up.

Recoil is very mild with a real load under the 142 grainer in this heavy gun, so there is no benefit there, but there was never a problem there to begin with.

I have no idea what velocity I'm getting here, and while I have been thinking about a Magnetospeed, I'm not there yet. The brass and primers look the same as they do when I use the normal load with H4350, but I forgot to bring my micrometer to measure in front of the web. The bolt lifted very easily, and I didn't get any other pressure signs. Everything seems safe. He said with reckless abandon.

If you're looking for an ultra light load to get in some practice with your .260, you might try H4895. I'm going to load up some 120 grain SMK's and try to get out to the range Friday, maybe get the bullets seated a little closer to the lands, and see how that works.

By the way, notice the extra 0.30 caliber holes in the top of the first target. The freaking Millennial in the next lane apparently has one of those California unionized public school educations, and he couldn't correctly count down the targets to figure out which one was his. He was appropriately apologetic when I advised him of his error, but it was the first time that had ever happened to me, so I just had a laugh with him about it. Dude was probably driving a Miata, you can't get mad at him!

[Fjold]

38.8 grains of H4350 is a light load and your barrel will probably only last for about 20,000 rounds or so.

I run 43.5 grains of H4350 in my AR style 260 and that's still a grain under max from Hodgdon.

[Khromo]

I'll take a 20K round barrel life!

But seriously, I am figuring I will shoot 2,000-3,000 rounds per year out of this rifle, so the barrel life matters to me.

I am going to load another series around that 43.5 grain area and see if things tighten up further.

This would be a lot easier if I could shoot better, but I gotta work with the tools available to me!

[Khromo]

They are tightening up at around 30.4 grains of H4895 behind the 107 grain Sierra MatchKing. Over two range sessions this load has produced groups measuring 0.44", 0.43", and 0.52".

This is accurate enough for informal target shooting and offhand practice at my skill level. I will fine tune a normal load for this gun using 142 grain Sierra MatchKings and Winchester 748 or H4350 powder, and use that one if the need ever arises.

It will be interesting to see if I can get the higher velocity load grouping much better than this one. The ceiling of my "skill level" should be banging me on the head pretty soon!