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Is there a rule of thumb on the minimum cartridge overall length you can load to.
I'm loading for 6.5x55 the rifle is built on a 308 action with a tight chambered match barrel. I am currently loading to fit the .308 magazine I am all ready at what would be an average .308 over all length but the 139 grain bullets are still jammed in the rifling and the bolt is stiff to close. Opening the bolt is stiff and it some times needs a bit of persuasion to open. To day the neck separated on a case and another sign of high pressure occurred so I immediately stopped shooting. Any info appreciated.

First thing is to determine an OAL that allows you to open and close the bolt without undue resistance. Jamming is going to cause a significant spike on chamber pressure. I am not sure what sort of powder or even load data you are using as a reference however I would say you need to drop at least 2.5 grains on whatever the manual says if you are loading to an OAL 2.800" versus the 6.5x55 standard of 3.150"

Tight chamber? How did that happen? Are you saying that your gunsmith has a 6.5x55 reamer that is ground under-size?

A 6.5x55 has a coal of 80mm and a .308 has a coal of 71.12mm......so if you load 6.5x55 to the same coal as a .308 surely the 6.5 bullet is seated too deep and causing over-pressure......or am I missing something?.

A friend had a 6.5x55Se built on a short action. You could load a round in the chamber via the ejection port but, you couldn't eject a live/full length round out of the ejection port because of the OAL.

If the bolt is stiff to close that's the first thing to suggest a problem, how does it feel loading a full length sized case with no bullet seated?

As above, if you're loading to 308 COAL of 2.8" and the rifle is chambered for 6.5x55 then a 139gr bullet shouldn't be near the lands unless it has a low ogive tangent, ie. round nose, these have to be seated further to avoid jamming into the lands.

[quoteA 6.5x55 has a coal of 80mm and a .308 has a coal of 71.12mm......so if you load 6.5x55 to the same coal as a .308 surely the 6.5 bullet is seated too deep and causing over-pressure......or am I missing something][/quote]

Sorry but mm means nothing to me you may as well be speaking in Russian my friend.


I don't know.
I'm just trying to determine if there is a cartridge length you should not go below.
I re loaded some 139 grain boat tail jacketed bullets using Vitavouri load data using a N150 starting load in the book it quotes a cartridge overall length of 2.990 I seated them to 2.900 so they would fit in the magazine. The bolt would close if you forced it. I fired one round and the neck separated and it was difficult to open the bolt. Obviously I did not shoot any more. To close the bolt I'm down to 2.880 and I probably need to go lower. How low can I go. Ill drag the Hornady over all length gauge out to morrow and have a measure. I have a box of A max Ill see how they measure up.

First try a full length sized empty case and make sure the bolt closes/opens without any force needed.

If you want to check the seating depth for your particular combination of bullet & chamber and don't have a comparator the easiest way is to cut a slot in both sides of an empty full length sized case neck with a Dremel disk or a hacksaw, partially seat a bullet and feed it into the chamber, this should allow the bullet to reach the lands, stop and be pushed back into the case. Eject and then measure the COAL, pull the bullet back out and repeat a few times to get a consistent reading. After you have the reading seat the bullet say 5 thou" further back into a normal FLS case and double check it chambers OK.

If you want the dubious benefits of my limited knowledge you're more than welcome to pop up tomorrow and we can look at it together.

Seems the minimum SAAMI COL is 2.750"...

http://www.saami.org/pubresources/cc_dr ... wedish.pdf

First try a full length sized empty case and make sure the bolt closes/opens without any force needed.

If you want to check the seating depth for your particular combination of bullet & chamber and don't have a comparator the easiest way is to cut a slot in both sides of an empty full length sized case neck with a Dremel disk or a hacksaw, partially seat a bullet and feed it into the chamber, this should allow the bullet to reach the lands, stop and be pushed back into the case. Eject and then measure the COAL, pull the bullet back out and repeat a few times to get a consistent reading. After you have the reading seat the bullet say 5 thou" further back into a normal FLS case and double check it chambers OK.

If you want the dubious benefits of my limited knowledge you're more than welcome to pop up tomorrow and we can look at it together.

Thanks for the offer but I'm under orders from her indoors to much shooting and not enough days out with her who must be obeyed so we are off out to morrow some were over the moors. May be Blakey Ridge for steaks. Yummy.

Good advice though I understand all that and I will spend all day to morrow measuring and following up on some of your suggestions.
Is there a rule of thumb that dictates the minimum over all length you should not go below is my question.