Trim length question

[opos]

Recently picked up an Interarms Mark X in 7mm Mauser caliber (7 x 57). Included was a big quantity of brass..cleaned, full length sized and primed. Only issue I have is that the fellow trimmed it to 2.220 and the trim length spec is 2.235 so he is 15 thousanths under..I'm guessing this is no sweat as it's a strong bolt action and the brass looks fine...I'm just used to trimming maybe 6-8 thousanths max. under trim spec and .015 seemed a little excessive...probably not an issue at all but I'm not familiar with the 7mm mauser..I load 06, 8mm Mauser and 7.62x54r and I do not load really heavy loads...mostly medium..don't hunt..just like to shoot a bit.

Thanks for any comments
opos

[BigBronco]

You should be fine. The SAMI spec is maximum length. Most trim about .010" under max length. An additional .005" under is insignificant if consistent. In fact you may not need to trim when you load them up another time.

[J-cat]

Cases grow when you fire them. I just had a FC 308 case grow .015" on me. Plus case length has nothing to do with action strength unless it's too long.

[AandO]

Good and proper.

I questioned a Lot of Speer .223 Brass a few years back which was even more seemingly off spec. Researched a little only to find out that Speer .223 is produced like that and it is good to go.......

Worked out real well.

[micro911]

For my gas guns, I trip .010" off the max. For my bolt guns, I trim .005" off the max. A little more will not hurt anything.

[pacrat]

Load em, Shoot em, JM2c

[Grunt81]

I'd trust these guys if I were you, especially since it's a bolt action which should head space off the shoulder. After your first firing, you'll see you shouldn't need to resize again, as others have stated. This means brass life should still be about the same, despite its initial trim length.

Without having to start a new thread, here's a curve ball. Do you all think the same goes for .223 in an AR? I'm working through 1200 PMC cases, but have another thousand or so of mixed headstamp, the majority being Federal. I've resized some before storing and measured some that are at 1.728" - 1.734". Book trim length is from 1.740"-1.760". What do you all think about this scenario?

[klewan]

Federal runs short, until I found that out, all the Federal went into another container. I think it's 1.740" they came out once fired. Not having to trim them is great.

[Grunt81]

Federal runs short, until I found that out, all the Federal went into another container. I think it's 1.740" they came out once fired. Not having to trim them is great.

Good to go, but would you reload it if it was 1.728" after full length sizing?

What should be the cut off point to where any shorter and it just becomes scrap brass in the recycling bucket? 1.730"?

[pacrat]

The purpose of the neck is to hold the bullet in alignment with the leade.

Rule of thumb is equivalent of 1 bullet diameter is sufficient for the purpose as long as concentricity is maintained. In real life situation, the actual chamber decides what will and will not work best or if at all.

[AandO]

Good to go, but would you reload it if it was 1.728" after full length sizing?

What should be the cut off point to where any shorter and it just becomes scrap brass in the recycling bucket? 1.730"?

As long as the neck holds the bullet and maintains concentricity you are good to go.

The Rule of thumb re: Trying to achieve "MAXIMUM OAL" is to seat your Bullets no less than the diameter of the Bullet being seated.

That same thinking applies here........

For example: A .224 Bullet needs to be set a minimum of .224 into the brass, a .308 needs to be set at a minimum of .308, etc....

My only real concern, assuming you have a properly sized case with a short neck would be potential pressure problems with extremely short necks.....

EDIT: the poster above me said the same thing and is correct in his answer to you. This is the right answer. I answered before reading all posts...

[gigante]

As everyone has said they should be fine. What I'd like to add is that I would make sure they chamber in the rifle. Just because they were FL sized doesn't mean the shoulders were bumped back enough. Nothing like loading up a bunch or rounds only to find out they won't chamber.

[Grunt81]

All points taken. Great information and I'm glad you brought up the higher pressure issue in short cases. I ought to back off at least 0.5 grains, if not more, if I ever decide to load those shorties.

[opos]

Got every thing sorted out...trims checked...loads made in a ladder for the next trip to the range...COL is fine..plenty of bullet in the neck and length fine for the testing..then when I sneak up on the load I want to use I'll fine tune th length...The thread sort of wandered off point but just wanted to say thanks for all that posted...I'm not new to loading..just never messed much with a very light projectile in a 7mm and when I saw the "over trim" just thought I'd run it past others...now to find time to shoot up about 20 loads and hope to find the sweet spot..then load, load, load.

[Grunt81]

Good luck.