.308 trim length

nell

Well-Known Member
Hi folks i'm about to start reloading for my .308 and was hoping somebody could let me know the correct trim length.
Will be using 155gr A max over N140 and Varget,would be good to hear any tried and tested combinations..

Thanks in advance

Nell
 
im using 43grains of varget Norma brass cci primners,155 amax. 1/4 inch group at 100m from bench rest.
 
Hey Nell
2.015 is a general safe trim length for all .308 rifles but all rifle chambers are not the same in this regard and as such I can go longer than this in my chamber before the need to trim. Best to measure you own. The whole idea of reloading
 
Hey Nell
2.015 is a general safe trim length for all .308 rifles but all rifle chambers are not the same in this regard and as such I can go longer than this in my chamber before the need to trim. Best to measure you own. The whole idea of reloading

Hmmm in that case the chamber of your rifle is badly reamed and out of spec....................... fairly common it seems in modern production :rolleyes:.

Me I check the cases for length when I start to inspect after cleaning and sizing then trim if required. At no time do I allow cases to be longer than the specified maximum or why else have any specs at all?
 
Trim length is not normally relative to your chamber. It is the length that puts the cartridge under the SAAMI specified length. As long as it is under SAAMI and uniform, you will do fine. Years ago I accidentally trimmed 100, 7.5x55 cases .040" too short. I shot in military rifle matches with them and never noticed a lack of accuracy because they were too short. ~Muir
 
Trim length is not normally relative to your chamber. It is the length that puts the cartridge under the SAAMI specified length. As long as it is under SAAMI and uniform, you will do fine. Years ago I accidentally trimmed 100, 7.5x55 cases .040" too short. I shot in military rifle matches with them and never noticed a lack of accuracy because they were too short. ~Muir

Hate to say this old chap ................................ but SAAMI is not the only organisation who laid/lay down such specifications... CIP also do this and to my mind SAAMI are a damned problem when they suddenly decide to redesign a cartridge that has been about for many decades or even longer. Off the top of the ole noggin they have done so with the .280 AI, 6.5x55, 7x57 ................ changing pressure limits moving shoulders changing head diameters :banghead: rather than make things safer they have created potential problems and mishaps waiting to happen.
 
Good grief! You're sounding like my Canadian great Aunt Ethel who loved to point out that the US wasn't the only country in North America that produced Grade A Fine maple syrup.:D

SAAMI is just my normal frame of reference and frankly old chap, many of the cartridges you folks enjoy are ones for which the SAAMI specs were the bench mark. The larger issue is that the poster not ad-lib their case length. Pick a reliable standard of reference and stick with it.~Muir
 
Good grief! You're sounding like my Canadian great Aunt Ethel who loved to point out that the US wasn't the only country in North America that produced Grade A Fine maple syrup.:D

SAAMI is just my normal frame of reference and frankly old chap, many of the cartridges you folks enjoy are ones for which the SAAMI specs were the bench mark. The larger issue is that the poster not ad-lib their case length. Pick a reliable standard of reference and stick with it.~Muir


Hmmm not sure we might not be related then as I think you will find, will have to check with the old uns in the morning, that I also had a Canadian Aunt Ethel... :rofl:.
 
I use the Sinclair chamber length gage insert. It allows you to determine the length of your rifle's chamber. We know Saami is there for safety reasons but as long as you trim .024 shorter than your chamber length [minimum] you are ok.
It is useful to know how much excess case length your chamber may have over published trim lengths in reloading handbooks.
Mine measures 2.045. Sooooooooo if I trim at minimum 2.021 I will be ok - almost does away with a trimmer. I find my case neck crack way before I need to trim - so far anyway.
 
I know nothing about the Sinclair tools and in fact have never even seen one. Never needed them and I doubt I will ever need them but I would not be happy to find out that the manufacturer or gunsmith had reamed a chamber out of spec. They're quick enough to boast about how super modern production is what with the sooper-dooper CNC machines yet it seems they cannot machine to drawings :-|.

As for case necks cracking :eek: yes it happens on occasion but so rarely I cannot recall the last time. Hmmm just thought it might be in the 25-06 but upon checking nope that was partial case separations on some FC brass. I brought three boxes of factory ammunition and used the cases for load development. Using one box a time so it seems I got about 8-10 reloads from the cases before they gave out. All cases were full length sized so perhaps the life could have been extended with less sizing.

Case neck failures are the result of either too hard brass, needs annealing, or improper chamber neck diameter resulting it too much working of the brass surely. So basically it comes back to a poor chambering job? Perhaps you should measure a fired cases neck diameter and see what it is and compare to the normal size in the cartridge specs. I expect the difference between fired brass and sized brass to be 0.004" or 0.005" on the neck diameter. Any more than that and I would be most unhappy.

Ahhh yes now I remember ........................... case neck splits. Some surplus .303 brass of South African origin. Very poor lot and gives hang fires possibly from poor storage conditions.
 
We're both cantankerous enough to share the same genes.:D~Muir

Ahhh the Canadian Aunt, great Aunt actually was Joyce, it was an Australian great Aunt whom I met when I was about 3 years old that had a sort of similar name.
 
I got about 8-10 reloads from the cases before they gave out. All cases were full length sized so perhaps the life could have been extended with less sizing.
How do they "give out" What do you mean by that?
I use the best brass- "Lapua" but even they crack eventually and they always go at the neck- not surprising as this is the thinnest part of the case.

Yes you don't have to use a chamber gauge. That is why we have SAAMI. All I am saying is that you don't have to be governed by the 2.015 Case length in .308
It's a good place to start but not the be all and end all.
 
I got about 8-10 reloads from the cases before they gave out. All cases were full length sized so perhaps the life could have been extended with less sizing.
How do they "give out" What do you mean by that?
I use the best brass- "Lapua" but even they crack eventually and they always go at the neck- not surprising as this is the thinnest part of the case.

Yes you don't have to use a chamber gauge. That is why we have SAAMI. All I am saying is that you don't have to be governed by the 2.015 Case length in .308
It's a good place to start but not the be all and end all.
 
How do they "give out" What do you mean by that?
I use the best brass- "Lapua" but even they crack eventually and they always go at the neck- not surprising as this is the thinnest part of the case.

Yes you don't have to use a chamber gauge. That is why we have SAAMI. All I am saying is that you don't have to be governed by the 2.015 Case length in .308
It's a good place to start but not the be all and end all.

By "Gave out" as I posted:-

"but upon checking nope that was partial case separations on some FC brass."

Which are like this:-

PB150095.jpg


Yes I crush the necks of scrap cases.

Classic case of web thinning due to full length sizing. As this was a new, to me anyway, rifle and I was doing load development all cases were full length sized and a check on case expansion kept whilst working up the loads. Just found a load suitable only to discover that Speer had stopped making the bullets :banghead: so back to the drawing board and a different bullet.

Now as for brass well the only loaded ammunition I could get to try this rife out within a reasonable travelling distance was some Federal and Sako so I brought a box of each and as he had 117 grain and 100 grain loadings in the Federal I brought one of each the Sako was 117 grain as I recall. Since then I have acquired some S&B 26-06 brass.

According to the Norma catalogue picked up at the Newark 2010 show they make the Lapua brass ..................................... hmmm cannot locate my copy at the moment which is strange however whilst looking I found an old Guns review magazine with the article about Colin's 350 Rigby magnum and tucked inseide was my original "83" Parker-Hale flier catalogue ...................... thank you .
 
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