New lapua brass - too thick

[newgun]

Hello,
After being lucky enough to purchase a new .260 remington rifle from GA Precision, I find that my new lapua brass necks are too thick to allow the bolt to close. The outer diameter on a loaded round is .293. Factory ammo that worked fine had an outer diameter of .290 or less.

My question is: How do I determine the perfect outer diameter for my loads? Should I just call GA Precision or is there a reasonably easy way I can work this out myself? I guess if I just turn the brass down to a loaded outer diameter of .290 that would work but I would like to know what the ideal outer diameter is.

Any help would be very appreciated.

Thanks,

Newgun

 

[halfmoanut]

On the barrel somewhere there should be a number indicating the neck diameter of the reamer used to chamber the barrel,if not you'll have to call the people who built the gun to find out.Brass will not chamber if the necks are too long also.Your loaded rounds should be .002-.003 under the number found on the barrel or whatever the diameter is that the person whom chambered the barrel tells you.You can turn the necks yourself but the proper tools are necessary.A dial calipers is not accurate enough to obtain the measurements required,you should use a outside micrometer.

 

[newgun]

o.k. thank you so much. It looks like I need to move to the next level. I want to make sure the limiting factor is all ways me.

newgun

 

[TheSnake]

.293 on your Lapua rounds do not sound too large. I do not own a 260 but .295-.297 sound like the norm for reamers I see out there. If you don't find the specs on the barrel, I would call the smith and see what the size was on the reamer before I start turning necks. You may have something else going on here.

 

[Redhighpower]

If the loaded round that works is .290, then I would neck turn the Lapua brass. You are only taking off .0015 inches per side. Have you tried loading a new Lapua case, unloaded to see if it will chamber? If it does not then resize the cases. Make sure the case length is the same as the brass that works. For a quick check, I would load 5 rounds and compare the groups between the factory ammo and your handloads. Good Luck.

 

[TheSnake]

How far is the bolt going before it stops? Is it way short or will it just not lock? Are you able to lower the bolt knob at all or is it not getting that far? Do you see any markings on the brass neck or on the case body after trying? Have you tried chambering a resized case without a bullet seated and does it chamber?

 

[newgun]

After using more force I got some of the rounds to chamber and it left a mark on the 120 gr. a max
The brass lookes unaffected. The mark is just past the ogive

I have no idea what is going on now

 

[newgun]

On the rounds that will not chamber, the bolt will go all the way forward but not down or it will just start to go down

 

[TheSnake]

Chamber your empty resized brass and see if it works fine. If it chambers fine, seat your bullet on the empty case and try it. If it then won't chamber, seat the bullet deeper and see if that corrects your problem.

 

[newgun]

My unloaded cases chamber like water on ice can't even feel them.

 

[jasonf]

SAAMI spec for the 260 neck is .297. Sounds like the chamber is short throated and you aren't seating deep enough. Either that or the cases are too long - SAAMI max is 2.035".

 

[Shynloco]

Newgun,
I'd call GA Precision as it very much sounds like you have a "dedicated chamber." Anytime I hear the word "Precision" in a rifle manufacturing company, that means that their chambered are custom cut to a specific size and that often, won't take some brass until it is also cut to the proper size. But make no mistake, Lapua is the best for producing the best results. Whats funny, is that I usually hear people gripping about the new Lapua brass being too thin for their chambers. But do call the company and take all the guessing out. I just gottan believe that nice new rig probably cost a few more dollars than a general production rifle. Lucky man my friend because I bet once you get it worked out, she'll put a big smile on your face at the range.

 

[FroggyOne2]

My Palma gun which has a .308/Tompkins chamber in it, will not take Lapua brass at all. But does fine with Winchester brass.

 

[DHD]

As you have noticed, it's not the brass. You need to seat your bullets a little deeper. It sounds as you do not own/have a comparator, and while measuring OAL with calipers will tell you only how long that particular loaded cartridge is, it works better than nothing. Do you still have the round loaded that was too long? Start there and seat deeper until the bolt closes. You can smoke the bullets, mark them w/a magic marker, etc., but the best way to measure OAL is with a comparator.

My $.02.............

 

[4xforfun]

After using more force I got some of the rounds to chamber and it left a mark on the 120 gr. a max
The brass lookes unaffected. The mark is just past the ogive

I have no idea what is going on now

HERE IS YOUR PROBLEM....Your empty brass fits like "water on ice", and your loaded rounds leave a mark on your bullet. You are loading them to long....bullets are are net seated deep enough. Adjust your bullet seater in a tiny bit and re test....if still to long , seat them a wee bit deeper. I am not sure what seating depth you are after....slight jam or jump... I always let my gun be the judge. Not being able to close the bolt is one (major) hint that you are to long. ;D

Let us know,
Tod

Sorry, I didn't finish reading the other posts after I got to your "mark on the bullet" post....Looks like you already got this info....good luck!