Can't trim to chamber length

[Davey Boy]

Ok I just measured my .308 Win chamber with the Sinclair chamber gauge. Got several readings between 2.070 and 2.072". Now Sammi states to trim to 2.015 -2.020". I wanted to get close so I could avoid the carbon ring that I have read about here as much as possible. Keeping the brass say .010 shorter than chamber length seems what most of you do on this forum.
I knew that I couldn't touch the lands with even the longest bullet possible, but thought I could trim to come close to the chamber length. Should I just trim to Sammi and call it OK?
I have used the Lee trimmer and Lee's easy trim in the past for trimming but just purchased the Trim it Two for adjustable length trimming.. Is there a brass producer who makes longer than normal brass?
Trying to keep things consistent but most of my brass is trimmed to 2.015.

Any suggestions? Just an occasional shooter having fun but trying to better my groups all the time.

Thanks Guys
Dave

 

[SGK]

Case trim length for .308 Win is 2.005" (and max case length is 2.015"), no? Hornady thinks so.

 

[Davey Boy]

Yes I meant max case length 2.015-2.020 My boo boo. Still a 1/4 mile to the end of chamber though.

 

[mikecr]

Don't see mention of your new case OAL.

 

[Davey Boy]

I load most to 2.810 COAL Is that what you mean? Ogive is somewhat less depending on bullet. But I'd like to load longer not using the magazine.

 

[retired]

do as you planned..trim to 2.07 minus .01...2.06
or pick a number in between..but much longer than the sammi spec

 

[Davey Boy]

do as you planned..trim to 2.07 minus .01...2.06
or pick a number in between..but much longer than the sammi spec

That's what I'd like to do but as I mentioned does any brass maker make .308 brass anywhere near that long. I'm doubting it.

 

[yotehater]

At least you shouldn't have to worry about jamming the neck into a bullet.

 

[Dos XX]

What is the OAL on your shortest piece of brass? Trim to that. Then shoot it. Then size it. Then measure them. Then decide if you want to let it grow or keep it there. If you clean correctly, carbon ring is nothing to worry about.

I trim mine to 2.006 every time I fire it.

 

[Davey Boy]

No that's true, can't even get the longest bullets to touch the lands, although have never tried Bergers.

 

[Davey Boy]

What is the OAL on your shortest piece of brass? Trim to that. Then shoot it. Then measure them. Then decide if you want to let it grow or keep it there. If you clean correctly, carbon ring is nothing to worry about.

I trim mine to 2.006 every time I fire it.

Most of mine come out to 2.015 as this is what the Lee trimmers are preset to trim too. But as I mentioned I just got a Trim it Two trimmer to be able to trim longer. Your right, so far I haven't had to contend with a carbon ring, Maybe I'm making to much out of wanting to trim longer, but though it might be beneficial as the chamber seems unusually long.

 

[yotehater]

No that's true, can't even get the longest bullets to touch the lands, although have never tried Bergers.

I mean with an extra .050" you don't have to worry about jamming the case neck into the free bore at the end of the chamber. That causes the case to pinch into the bullet increasing pressure. It sounds like your have a lot of free bore before the rifling starts too. Have you thought about a Cerrosafe cast to see how long it is?

 

[MagnumManiac]

Regardless of cartridge, the ONLY time I trim and keep cartridges to chamber length is with my target/precision rifles. This is to reduce the carbon ring, as I have several comp rifles that will have 200 rounds down in a weekend WITHOUT a full cleaning between comps.

Doing this on a hunting rig is not what I would recommend or do.
In fact, in my belted mags, 264WM, 270 Weatherby, 300WM, 338WM & 375 Weatherby I trim to max case length knowing there is still .030”-.040” wiggle room to the end of the chamber neck. You don’t regularly shoot a hundred rounds or more in a hunting rifle between cleanings, so a carbon ring is unlikely to happen.
I also measure my chambers, just as you have, so I KNOW what I’m dealing with.
This is a very good thing to now, as I built a 338 Edge with a tight neck, this would produce pressure problems during a string as the carbon ring would impinge on the neck. After re-cutting the neck from .0015” clearance to .003” clearance, the problem disappeared. I no longer build ANY rifles with excessively tight necks, as I NEVER saw a difference on target. I still turn my necks on my comp guns however, as it is required for accuracy, but no longer for clearance.

Cheers.

 

[Davey Boy]

I mean with an extra .050" you don't have to worry about jamming the case neck into the free bore at the end of the chamber. That causes the case to pinch into the bullet increasing pressure. It sounds like your have a lot of free bore before the rifling starts too. Have you thought about a Cerrosafe cast to see how long it is?

Yes lots of free bore. As to casting the chamber, probably not worth it as it's an old gun, and to fix that large amount of free bore I'm better off putting that money into a new firearm of the same caliber since I have all the brass and reloading tools for it. I have some brass that measures 2.020 so might let them get to that length and trim all of them there and be done with it. Not sure if I could reform 30.06 to .308 and get a longer than usual neck. Sounds like too much work though. Easier to buy a new gun.

 

[Rsadams]

Yes lots of free bore. As to casting the chamber, probably not worth it as it's an old gun, and to fix that large amount of free bore I'm better off putting that money into a new firearm of the same caliber since I have all the brass and reloading tools for it. I have some brass that measures 2.020 so might let them get to that length and trim all of them there and be done with it. Not sure if I could reform 30.06 to .308 and get a longer than usual neck. Sounds like too much work though. Easier to buy a new gun.

Just re barrel it with a nice barrel and enjoy it... Barrel are going to get shot out... The best way to avoid carbon and copper is to clean it and not let it build up in the first place...

 

[Davey Boy]

Just re barrel it with a nice barrel and enjoy it... Barrel are going to get shot out... The best way to avoid carbon and copper is to clean it and not let it build up in the first place...

Yes that's an option to consider

 

[Rsadams]

Yes that's an option to consider

What kind of Rifle..? If it's a Savage it's something you can do yourself.... Are you sure your reading the measurements correctly..? That's a lot of free bore... If it hasn't had a lot of rounds down the tube it shouldn't be wore out that much... .308 has good barrel life...

 

[243winxb]

Now Sammi states to trim to 2.015 -2.020".

No, typing mistake?

Its a maximum case length of 2.015" it can be trimmed back as much as .020" , but normal trim to is 2.005"

There is a "safety zone" built into the chamber, just in case a long cartridge gets loaded.

I keep my brass at maximum for my single shot 243 win.

 

[Shynloco]

Davey Boy,
FWIW, most Reloading Manuals show to trim brass to 2.005. So that is what I trim all my brass to and keep it there. But when it comes to the overall length of a loaded round, I measure by Ojive and could care less about what overall length reads. And that Ojive measurement has been determined by a seating depth wherein the rifle shoots most accurately. SAAMI spec are guides and not absolutes. The rifle itself determines the absolute and never forget, each rifle is unique and what works the best in one rifle, may not even be close in another. I've seen and had a few .308's work great with "jam" while others hate "jam" and want "jump." And oft times that is determined by the bullet you are shooting. I used to be able to "jam" with a factory barreled Ruger M77V and upon changing the barrel with a new chamber (using a different reamer), the new barrel loved the jump and hated the "jam" using the identical bullet, a Sierra 168 gr HPBT. So don't get hung up the Overall Length thing as the rifle may well determine it's own likes and dislikes which make a huge difference when it comes to accuracy.

Alex

 

[Webster]

Ok I just measured my .308 Win chamber with the Sinclair chamber gauge. Got several readings between 2.070 and 2.072". Now Sammi states to trim to 2.015 -2.020". I wanted to get close so I could avoid the carbon ring that I have read about here as much as possible. Keeping the brass say .010 shorter than chamber length seems what most of you do on this forum.
I knew that I couldn't touch the lands with even the longest bullet possible, but thought I could trim to come close to the chamber length. Should I just trim to Sammi and call it OK?
I have used the Lee trimmer and Lee's easy trim in the past for trimming but just purchased the Trim it Two for adjustable length trimming.. Is there a brass producer who makes longer than normal brass?
Trying to keep things consistent but most of my brass is trimmed to 2.015.

Any suggestions? Just an occasional shooter having fun but trying to better my groups all the time.

Thanks Guys
Dave

Like others said don't worry about the carbon ring. No reason to have to touch the lands if it's an older factory rifle you shoot for fun. Off the lands works fine in many rifles. I don't want to touch the lands in any of my varmint rifles to make sure I can eject a loaded round without the bullet stickig in the bore and dumping powder in the actio