.308 Case Length

[20series]

Gents

According to all the info I've found, the correct case length (base to neck) for.308 Win is 2.015 inch.

Having not bothered too much about it in the past I thought I'd better check my now fired 5-6 times Lapua brass to see if I (or Santa) need to invest in a case trimmer only to find the brass I checked is actually shorter averaging about 2.010 - 2.013.

Since I'm a bit new to reloading can anyone tell me if its going to make any difference.

I'm using Redding full length dies,

Cheers

Alan

[loiner1965]

Originally Posted by 20series

Gents

According to all the info I've found, the correct case length (base to neck) for.308 Win is 2.015 inch.

Having not bothered too much about it in the past I thought I'd better check my now fired 5-6 times Lapua brass to see if I (or Santa) need to invest in a case trimmer only to find the brass I checked is actually shorter averaging about 2.010 - 2.013.

Since I'm a bit new to reloading can anyone tell me if its going to make any difference.

I'm using Redding full length dies,

Cheers

Alan

you are probarbly using low loads so the case is not growing etc....nothing to worry about but what are your loads

[20series]

Cheers for the reply

I'm running 155gn SMK's with 42.5 gn of Vit 140 at 2.80 OAL, this generally gives me a 1MOA group at 100 yards.

I haven't chronoed it yet but I'm off to Bisley at the end of the month to have a go at 900/1000 yards so I'd better get something sorted before then so I can get an Idea for come ups.

I just wondered really wether the length makes all that much difference.

[loiner1965]

Originally Posted by 20series

Cheers for the reply

I'm running 155gn SMK's with 42.5 gn of Vit 140 at 2.80 OAL, this generally gives me a 1MOA group at 100 yards.

I haven't chronoed it yet but I'm off to Bisley at the end of the month to have a go at 900/1000 yards so I'd better get something sorted before then so I can get an Idea for come ups.

I just wondered really wether the length makes all that much difference.

it will be hard to close the bolt if the length got too much so just keep checking and trim when needed

[bullbarrel]

Originally Posted by 20series

Cheers for the reply

I'm running 155gn SMK's with 42.5 gn of Vit 140 at 2.80 OAL, this generally gives me a 1MOA group at 100 yards.

I haven't chronoed it yet but I'm off to Bisley at the end of the month to have a go at 900/1000 yards so I'd better get something sorted before then so I can get an Idea for come ups.

I just wondered really wether the length makes all that much difference.

I think you'll find you might need a bit more powder or lots of up clicks.

I use a similar load and needed to go to 45grs to get near the RG velocity and even then it was quite a bit under.

Would definately suggest you chrono it and put the results through a balistic calculator before you start on 900 yards and bounce rounds off the mantlet

And as for the cases, my lapua have been reloaded loads of times and I've never had one go over 2.015" and need a trim.

Happy shooting.

[20series]

Thanks for the replies and advice gents, I'll get some loading done this week I think and toddle off to do come chrono checks next weekend

ATB

Alan

The 2.015" you mention is the maximum SAMMI length and the chances are your chamber is a good bit longer then that. The best thing is to get hold of a chamber length gauge and measure it yourself.
You want to be a minimum of 15 thou short of the actual chamber length as if it grows any longer, there is a chance that the brass may hit the end of the chamber and almost crimp the bullet upon firing and this raises pressures dramatically.

Kev.

[20series]

Originally Posted by Beer Hunter

The 2.015" you mention is the maximum SAMMI length and the chances are your chamber is a good bit longer then that. The best thing is to get hold of a chamber length gauge and measure it yourself.
You want to be a minimum of 15 thou short of the actual chamber length as if it grows any longer, there is a chance that the brass may hit the end of the chamber and almost crimp the bullet upon firing and this raises pressures dramatically.

Kev.

Kev

Ahh that makes more sense if it's a max length, I assumed it was the nominal.

I did measure my COAL and it came out at 2.88, I haven't got a clever as playing with my OAL sizes yet to see if I can improve the groups any more.

cheers

Alan

[harry mac]

Remember there are two case length measurements. The maximum, and the "maximum trim to" length. The maximum trim is actually the minimum case length; if that makes sense. Also you don't mention if the cases you were measuring were resized or not. When you measure the case length you should resize first as this will give you a truer indication of the case you will be putting in your rifle.
If you only neck size your cases stretching will be minimised (and case life improved), but every so often you will need to either full length resize the case or at least bump the shoulder back a little.

[MikB]

Originally Posted by 20series

Kev

Ahh that makes more sense if it's a max length, I assumed it was the nominal.

I did measure my COAL and it came out at 2.88, I haven't got a clever as playing with my OAL sizes yet to see if I can improve the groups any more.

cheers

Alan

With 155 SMKs my only comment would be that your engagement of the bullet with the caseneck is pretty short. I thought mine were seated out a long way at 2.82", but yours are 60 thou further. Do you know how far off the rifling leed you are? If you're getting good results, I reckon I might try your OAL!

Regards,
MikB

[Ackley]

Originally Posted by Beer Hunter

The 2.015" you mention is the maximum SAMMI length and the chances are your chamber is a good bit longer then that. The best thing is to get hold of a chamber length gauge and measure it yourself.
You want to be a minimum of 15 thou short of the actual chamber length as if it grows any longer, there is a chance that the brass may hit the end of the chamber and almost crimp the bullet upon firing and this raises pressures dramatically.

Kev.

as the man says,forget what it says in the books you need to measure your chamber correctly,you will find your brass will be a mile short and will never stretch to the chamber length,
personally I wouldnt worry about the length once you have fired your brass once measure and trim to the shortest length,you will find the LEE case trimmers are no good for this as the rod is far too long thats why you need to use a proper case trimmer like a WILSON
to get the best out of your rilfe you will need to adjust your COL forget what it says in the book your rilfe may like a 100 thou jump

[20series]

Originally Posted by MikB

With 155 SMKs my only comment would be that your engagement of the bullet with the caseneck is pretty short. I thought mine were seated out a long way at 2.82", but yours are 60 thou further. Do you know how far off the rifling leed you are? If you're getting good results, I reckon I might try your OAL!

Regards,
MikB

Mik

The 2.88 is my chamber measured using a length gauge, I usually set my COAL to 2.80, sorry my terminology was probably incorrect like I said I'm still learning all this reloading lark and I'm only a thick sparky

Alan