260 REM Seating Depth

[Mark 260]

I'm reloading .260 REM for the first time, the bullet is much longer than my other calibers. I’m using the Berger 6.5mm 140 gr Match Hybrid Target Bullets. My reloading manual is telling me that the O.A.C.L. should be 2.800”, is this correct for such a long bullet?

 

[alf]

OAL is dictated by maximum magazine length and/or freebore dimensions, not manuals.

 

[mikecr]

+1 Alf
You can't look up best COAL/CBTO in a book. You measure and test to determine it.

 

[BradY]

As has been mentioned you need to find you seating depth relative to the rifling in your chamber. In a 260 wildcat f class rifle I had success jamming the hybrids 10 thousandths into the lands, in fact it shot the hybrid and the 140 vld to similar elevation and windage at 1000 yds both with a 10 thou jam.

 

[22BRGUY]

I noticed you just joined this forum recently. Wondering if you know how to make a dummy round or otherwise check your actual rifle/chamber/bore dimensions?. More info about your rifle would be helpful
Best Wishes

 

[Sniper338]

OAL is dictated by maximum magazine length and/or freebore dimensions, not manuals.

this....

gotta measure it

 

[savagedasher]

The manual is telling you the pressures of the load when the bullet is seated at 2.800 in a normal chamber. If the chamber has a short FB or you seat them in the lands the pressure can be as much as 5000 PSI higher. that the reason you start 10% low and work up. 2.800 is also the norm for magazine length. Start low and work up Larry

I find Hybrid like to be jumped VLD like to be near or in.

 

[jcampbellsmith]

OAL is dictated by maximum magazine length and/or freebore dimensions, not manuals.

Spot on. I've one 260 Rem with a HS magazine and that allows me to load rounds to 2.8 inches. My other 260 Rem has a Wyatt's Extended Magazine Box and this allows me to load rounds up to COAL of 3.075 inches.

Regards

JCS

 

[Mark 260]

2 of the guns are gas 260 test guns built off of an AR10 platform and 1 is a custom bolt gun. I shot 100 rounds of factory ammo threw each to test the guns for accuracy, the 110 grain round barely makes in the AR110 magazine. One of the gas guns is a gas piston gun and the other is a DI gun, i have no issues loading for the bolt gun but i would like to use the same ammo for all of the guns.

My only question is: With a COAL of 2.800" with Berger 140 grain hybrid, is the bullet seated to deep?

I also tried re-sizing .308 cases for the 260 since i have a never ending supply of Hornady and Raug brass, but after the re-sizing my cases are just a little short of spec.

 

[jlow]

Seating your Berger 140 Hybrid to a generic 2.800 OACL is certainly not the best way to take optimal advantage of the accuracy of the round as with these bullets, you usually seat them to almost touch the lands (I use 10 thousands off) and seat them deeper to find the optimal OAL. Seating them that deep will also as you say significantly decrease case volume, increase chamber pressure, and reduced the amount of powder you can put in the case. It will also seat the bullet deep enough that it will likely be in the donut area of the case neck.

Making one load for all the guns sounds like a great idea but that is only good if all your guns likes the same load which is not likely, plus you would end up loading for the lowest denominator which would be the gas guns which is not what you really want to do.

 

[Mark 260]

Thanks jlow

The .260's are new guns to me and i would like to get most out of my rounds

 

[jcampbellsmith]

Thanks jlow

The .260's are new guns to me and i would like to get most out of my rounds

I've 2 x 260 Rem. I'm running one on Nosler brass and the other on Lapua brass. I'm treating them as if they were two different calibres. Powder type and bullets may be shared, but each will have the full length resizing die set differently.

I suggest you work up a load for one rifle at a time.

Regards

JCS

 

[22BRGUY]

Thanks jlow

The .260's are new guns to me and i would like to get most out of my rounds

I've 2 x 260 Rem. I'm running one on Nosler brass and the other on Lapua brass. I'm treating them as if they were two different calibres. Powder type and bullets may be shared, but each will have the full length resizing die set differently.

I suggest you work up a load for one rifle at a time.

Regards

JCS

Gotta agree totally with this comment. Rifles are like women, they're all different even if they wear the same clothes or are even twins, and they all like different things.
Best Wishes

 

[barefooter56]

Mark260,
If you are looking at the Berger reloading manual. Our loads are listed for magazine length ammunition. Having said that. What you will find is that due to the length of the bullet v the cartridge case length you will probably end up with rounds that will no longer cycle through the magazine due to their over all length and have to be single loaded . This is especially true with magazine fed rifles like the AR platform. For bolt action rifles that have or are built on a long action and chambered for the .260 the issue of the round not fitting or feeding through the blind box magazine is usually nonexistent. If there is an issue then an oversize magazine can be retro fitted to the rifle like stated previously ( Wyatt extended magazine box). Please contact us at techsupport@bergerbullets.com if you have any questions.