.260 brass questions!

[Teufelhunden]

I've got flat primers and stiff bolt lift from Lapua brass in a prefit Shilen barrel for Savage. After much troubleshooting I now want to try different brass. Or neck turning. I suspect a tight neck-chamber fit. I'd like to come away with something usable even if this doesn't fix the problem.

I've got 40 pieces of once fired Lapua brass, and another 20 twice fired, that will need neck turning to make work if that's the problem.

Rem brass is available online for $45 shipped per 50 count. I found an article that states the neck thickness of this brass, and it should work. I'm not sure I want this brass if it doesn't solve the problem,though, unless somebody convinces me otherwise.

Win 7-08 brass is somewhat less expensive at the local store. Does anybody have a neck thickness dimension for unturned Win 7-08 brass that's been necked down to 6.5?

What is the least expensive way we can put together an effective neck turning setup? Are those $60 unmounted hand turners any good?

Thoughts, musings, answers?

 

[22BRGUY]

I'd suggest getting some cerro safe and casting the chamber to find out first exactly what you have for dimensions in there....Best Wishes

 

[Redhighpower]

Lapua brass is thicker in the neck than Remington. Remington .260 brass works for me . The hand neck turners work great. I use a electric screw driver on mine. I just neck turn to about .012 wall thickness. What load are you using? Flat primers and stiff bolt to me says your loads are to hot, drop a full grain and see what happens.

 

[gunsandgunsmithing]

What do your loaded round and fired cases measure at the neck?--Mike

 

[Teufelhunden]

I should have posted this up front.

http://forum.accurateshooter.com/index.php?topic=3788024.0

The easiest thing for me to do is have you read it, but in a nutshell I checked and adjusted headspace, checked bolt to barrel stub and reduced load to what should be a safe 42.0gr H4350, CCI LR primers, 139scenar and still got signs.

I'd suggest getting some cerro safe and casting the chamber to find out first exactly what you have for dimensions in there....Best Wishes

That had crossed my mind but something tells me this would be more of a project than I'm ready to undertake. I think I want to save it as a last resort. 30ish dollars for a bag of 7-08 brass tomorrow could tell me something, and allow me more shooting in the future regardless of outcome.

What do your loaded round and fired cases measure at the neck?--Mike

Using digital calipers I get .299" fired and .298" loaded.

 

[gunsandgunsmithing]

Not to be argumentative, but, in the other thread, you stated you had .299 loaded and .300 fired. This could be the problem. You have a head scratcher, but after reading the other thread, I come to pressure as being the cause(without seeing it). The pressure could be coming from the doghnut and/inconsistencies in neck thickness. Have you shot it over a chrono. I've seen starting book loads be hot in some guns.
Bottom line, IME, your problems come from either pressure or sizing die/chamber issues. IIRC, from the other thread(I'm trying to keep things straight), the die was eliminated and was sizing sufficiently, correct me if I'm wrong. A chrono will tell you if your velocities are where they should be for a given powder charge.
I'm guessing high pressure from too little neck clearance, but to be honest, boucing between all the posts in two different threads, I hope I'm keeping up with all the pertinent details.
You're neck clearance is too close to trust calipers!

 

[pdog2225]

I have experienced a problem very similar to yours. I use a savage mdl 12 with a shilen prefit 260rem, 8twist, 26" long. I bought 400 new Norma .243 cases and thought that these would be better than the R-P cases I was using. I use 42.0grs of IMR4064,RPcases,120gr SMK(moly)and Fed210M primers and have no pressure issues. So I loaded 5 of the Norma cases and the first two were very hard to chamber. The first round blew out the primer! So did the second one. At this I stopped and pulled the remaining bullets. Even the new empty expanded cases were very hard to chamber.
My problem was the headspace was way to tight (bolt stops at halfway on the go gauge). I wanted minimum headspace for long range accuracy. If I want to use the Norma brass then I need to re-headspace my chamber for it.
This an accurate rifle and load. Last monday (6-11-12) I killed my first 1275yd prairie dog with it.

 

[fm1947]

I had issues with my 260 when i first loaded for it as someone else said some of the data is to hot I split a case in half remington once i cut it back where it wasnt blowing out primers i then loaded my lapua brass all is good now, shilen usually puts neck dimension on barrel i really doubt you have a tight neck , call them, my lapua brass is .015 neck wall thickness.

 

[Elkbane]

Teufelhunden,
With the measurements you gave (.298" O/S neck on loaded round), those are pretty thick necks, even for Lapua brass. (.298-.264)/2 = 17 thousands neck wall thickness. Most of the Lapua 260 brass I've worked with is 15-15.5 thousands neck wall thickness. You must have a "thick" batch, and if they are that thick in the necks, they are probably thick on the case walls as well, which would lead to reduced case volume and may be causing your pressure problems.

You could buy a 50 round box of Norma (or Nosler - same) brass. It's pretty uniform and typically has 14.5 thousand neck wall thickness. .00145x2 + .264 = .293, which would give you adequate clearance. But if it were me and I had a batch of nice thick brass like yours, I'd turn the necks to 15.5 thousands or so and have a good set of cases with really uniform necks. And just about the right delta between fired round and sized neck for using bushing dies without an expander button. You can adjust your load to account for case volume......
Elkbane