Working With "Maximum Trim Length"

[fmnnc]

New to reloading rifle cases, so here goes:

The data sheet that came with my Lee Reloading Dies (.223 Remington) states that the "maximum trim length" is 1.760 inches. My Modern Reloading book states the same dimension for the length of the case.

Question:

Is this the maximum length that the case can be and if it is over that it needs to be trimmed?

or...

Is it the maximum length it can be trimmed to and if shorter. it is no good?

I recently purchased some new Winchester brass and they measure 1.754 inches. I also have a case trimmer and it seems to trim a few of my fired cases to the same 1.754 length.

All of this would suggest that the first question I asked seems to be on target. As such, what is the minimum length the case can be? If it is less than the trim gauge is it a NO GO case?

Thanks...:banghead:

 

[Walkalong]

The "max" case length of 1.760 listed is for a SAMMI spec chamber and it will keep you out of trouble if you keep under that unless you run into a "short throated chamber" which is not very likely.

The brass can be as long as YOUR chamber will allow, but max trim lengths are a great guide and as I said, will keep you out of trouble.

I trim my .223 brass, after sizing, to 1.750 (as do many others). This is a good "happy medium" as it is not to long and not to short.

Trimming brass shorter will not really hurt anything, but gives less neck length to hold the bullet securely.

 

[oneeyesnipe]

I Second Walkalongs Theory Listen To This Guy Although I Try To Keep All My Brass The Same Length For Crimping Reasons I Trim Mine From 1.750 To 1.755 Better Safe Than Sorry Good Luck And Take Your Time

 

[Slamfire]

I too trim my .223 cases to 1.750" as that number is easy to remember, and is easy to find on my dial calipers.

Generally I trim about 0.015" below max trim length. But I am getting to be of the opinion that as long as the case will hold your bullet, nothing bad is going to happen if you trim more than that.

Early in my reloading life I found that too long of a case is very bad. I had 30-06 cases get out in the throat and not expand enough to let go of the bullet. That blew some primers.

I also have observed that brass "grows" the most on first firing. I cannot think of a once fired case that was not way over max after sizing.

Trimming is a safety thing more than anything else. Just keep the case neck out of the throat.