Brass and poor accuracy

[montana_native]

I recently had a 260 built. Years ago, a friend bought thousands of pieces of LC 308 brass. I culled 100 pieces head stamped LC 88 and necked them down. I've tried this brass in two different 260s. One was a Shilen barrel and mine is a McGowen. Both of them were built by a very competent smith. Both of them can't seem to get below 1 MOA with 100 or 140 Amaxes.

Is it time for new brass?

 

[jonbearman]

What load are you using,what dies,what kind of prep work etc. LC brass is good brass and can be made to shoot very well. What neck thickness do you have after necking down?

 

[jonbearman]

What twist rate is the barrel.

 

[montana_native]

8 twist barrels. I just sized, trimmed, deburred flash holes and chamfered the brass.

 

[navyrad8r]

Montana,
I do the same with my .260, 39 gr IMR4064, wolf, but 123 lapua/ 120 berger/ 123 amax..firing pin is bushed, shilen select 30.25" 8 twist. maybe check your neck tension as jon eluded to? to you re-expand right before you load? what is the load? FWIW PM me if you need help with a new batch of brass.
cheers,
Doc

 

[JaredCO]

I shoot lc 72 match in my rock creek barreled savage. One pass through fl die and neck turn. Having great success around 1/2 moa with h4350 and 142s. It's all I need for the matches I shoot.

 

[brian427cobra]

Ok we'll first off 308 brass is too short for a 260 chamber, that's problem 1, my 260 hammers .2-.3 groups all day long with Win 7-08 or 243 brass resized to 260, all my brass gets trimmed to 2.030, brass too short burns up chambers faster than normal, from my experience 139 Scenars like to be at the lands, 140 VLDs .010 in, 140 Amax .010-.020 jump, 142 SMK at least a .030 jump, CCi primers and H4350, Rem 260 brass sucks, about the time it needs annealed the pockets are gone, but its soft and accurate for 5-6 loads, all the pills listed are launched around 2775-2810.

 

[jonbearman]

In this case,what is the neck thickness,it may require turning to have enough clearance in the chamber. I realize his brass is short but that is what he has and I would recommend real 260 brass like lapua.It is expensive but it works or maybe the nosler brass to get a longer neck.I agree with you brian but I think he may be on a budget inially and I was trying to find out the whole background so we could help him.Hi Doc,I hope you did good at your match!

 

[jonbearman]

Mcgowen's print calls for a .293 resize diameter,tell us the loaded round diameter at the neck. Check it in a couple places near the neck shoulder junction and towards the end of the neck.

 

[searcher]

Just curious. Did the Amax's shoot well in these barrels before with different brass? If this is also the first time for the Amaxes, don't give up on the brass. I've got a Krieger-barreled 7 mm Rem. Mag. that shoots 1 1/2" groups with the big Amaxes! (This is a hunting rifle w/pretty skinny barrel) Because the Amaxes shot so well in my .223, I mistakenly took a big gamble that I could make them shoot also in the 7 mag. I tried Winchester, Remington and finally, Norma brass and five powders. It shoot other bullets just fine. Most guns are far less critical of brass than bullets....

 

[montana_native]

I realize I should have provided more info.

Both rifles were new and have never seen anything besides this LC brass. The brass was annealed prior to the first loading. I've tried seating depth from 0.010" into the lands to a 0.050" jump. Powder is H4350 and I've tried CCI200s and BR2s.

Rifle is an FN PBR that has been trued and squared. Just seemed odd that two rifles would suck so I figured it might be the brass since I knew nothing about it.

I am going to start the search for good brass...likely Lapua. I was just being a cheapskate in using this brass thinking I could make it work. Anyone want to part with some Lapua brass? ;D

 

[searcher]

Because you have a bunch of the LC brass, if your resized brass measures out O.K. as the other guys have pointed out - and this is not a full-blown target or bench rest rifle (I am thinking it is a hunting rifle?), I'd try another bullet like a Berger. Will cost you just over half of what one box of Lapua will cost you to buy a box of their bullets. If the brass works well for your intended purpose using a different bullet - far better than buying Lapua only to find the Amaxes still don't shoot - then you'll probably be buying more bullets anyway- if closing the group is your objective. I've loaded many types of brass with many types of bullets over the years and I REALLY believe that brass, while they vary in quality and what works with your bullet best, is not nearly as big of a factor as the bullets in most applications. The good news is your LC brass is in high demand with many shooters if it doesn't work out. Good luck!