Case length

[BoogNasty]

I seem to be spending a lot of time reloading rounds that I just end up putting into steel targets or killing paper, so my question is

1. Does case trim length matter if the OAL is still within +/- .10?

2. A better way to get the powder charges the same for every round without having to dump or tumble in that extra grain, I am currently using the standard manual RCBS powder measure. I am getting inaccuate powder charges due to powder clumping up in the measure.

Any tips would be awesome, thanks

[highpower790]

I think that at some point if cases are not trimmed then head space issues could be a problem.Trim to min length,load to oal,then retrim as necessary...maybe every 3-4 reloads.
For my charging needs I powder drop every charge,best not to worry about +/- a couple tenths accounting for your abilities and quality of firearm.

[ducky_0811]

+/- .10" (one tenth of an inch) is quite a lot. Just about every manual I've read lists max case length as +.010" over trim length. If you let your brass get too long head space won't be the issue in a bottle necked, rimmed or belted base. It will in a strait wall case as long as it's not a rimmed case. What will happen if your neck gets too long is that you'll end up cramming the neck of the case into the start of the lands in the barrel. This will effectively "crimp" the brass into your bullet, creating some dangerous pressure issues aside from accuracy problems which will be the least of your worries.
Measure your casings after each resizing and trim to length when necessary.

[BoogNasty]

Some great info, and i haven't short any untrimmed brass yet. The problem I am having is my ziptrim brass trimer was trimming to short, about .10, i didn't know if this would cause an issue or not

[BoogNasty]

haven't shot* (typo)

[ducky_0811]

Are you sure it's .10? Or .010? While I don't believe there would be any safety issues with shooting a case that was that short, neck tension would surely be effected. .010 short of trim length would be fine, it'll stretch back After a few sizings, .10 is a bit too much for me

[BoogNasty]

As you were .010, trim length is supposed to be 1.75 and some of my cases are 1.735, some 1.740, I need to adjust my trimmer but before I loaded these cases just wanted to ensure i would be ok.

I am just unsure how "spot on" I need to have each round for plinking ammo. If I want to hold tight groups I know i want each round to be close, but steel targets is what i shoot for the most part.

[highpower790]

As you were .010, trim length is supposed to be 1.75 and some of my cases are 1.735, some 1.740, I need to adjust my trimmer but before I loaded these cases just wanted to ensure i would be ok.

I am just unsure how "spot on" I need to have each round for plinking ammo. If I want to hold tight groups I know i want each round to be close, but steel targets is what i shoot for the most part.

For myself I would trim to no less than .005 below min,this would be a benefit to trimming .

[BoogNasty]

thanks for the advise

[J-cat]

Why are you trimming that short? Your chamber will prolly take cases in excess of 1.780". Measure your chamber. Then determine trim length.

[CK_32]

Accuracy wise? Meh hardly unless your shooting match grade groups.


Reliability yes. I found out this weekend what happens when you skip trim to length. Half of my batch would not chamber or eject. .003 to .005 over length literally stops the gun. Usually takes a good wack rack to clear the round.

https://m.youtube.com/watch?v=KPT0IyKfXhA

Last round is one of them. Was dealing with this all day. This one wasn't bad, but the others I had to slam the rifle brace on the floor pretty good to get it free. Tugging the CH wasn't happening.

[BoogNasty]

I trimmed that short on a fluke, after i trimmed about 50 cases i noticed that some were shorter than others and measured each one. Lessons learned I guess, measure after each case

[BoogNasty]

could short case lengths cause misfires? like a soft primer strike?

[J-cat]

No.

The case headspaces off the shoulder, not the case mouth.

[Wrangler John]

Case Trimming

Here is my case trimming WIKI:

Rimless pistol cases, 9mm Luger, .40 S&W, .45 ACP, etc., headspace on the case mouth, do not trim below the published SAAMI case length listed in reloading manuals. Excessive headspace on these can cause hang and failure to fire incidents, or a burst case. Pretty much leave them alone. It's true that too long a case may tie up the pistol, preventing it from going into battery, and these will need trimming or discarding, but these cases stretch little due to the lower pressures they generate.

Rimmed handgun cartridges such as the .38 Special, .357 and .44 Magnums headspace on the rim, trimming will not effect headspace. However, inconsistent trim length will effect the strength of a crimp. It is my policy when loading competition ammo for revolvers or single shot pistols, to trim to the shortest case length in a batch of new unfired brass. This maximizes crimp consistency, with the crimp a major part of consistent powder ignition. In large volume cases, a heavy roll crimp is necessary, along with magnum primers, to consistently ignite spherical powders such as W-296 and its twin H-110 with heavy deterrent coatings. The actual length is not as important as all cases being the same length within the range of tolerance. Usually maximum trim length should be no more than 0.010" under maximum case length. Cases that are way out of range can be sorted together and used as a separate batch.

The above also applies to rimmed straight rifle cases for the same reason. This is especially true of tubular magazines that require a crimp to prevent magazine spring pressure and recoil forces from driving the bullets into the case. This also applies to bottle necked rimmed cases, which also headspace on the rim, such as the .30-30, .348 Winchester and the others. I used to form .30-30 Winchester cases from .375 Winchester straight cases that formed about 0.0625" short. No problem, the cases were stronger to support heavy charges in a Contender, and that missing length is meaningless. Those cartridges won many matches.

Belted magnum cases headspace on the front of the belt, regardless of case shape, either straight walled, as in the .458 Winchester, or bottle necked as with the 7mm Remington Magnum. Maintain trim length up to 0.010" below the maximum length.

Bottle necked rimless cases headspace on a datum line on the case shoulder. Trim length will not effect headspace. Trim to any length desired as long as it isn't excessive, but maintains case length under the maximum. Here again consistency is more important than the actual length, especially when crimping bullets.

Most handloaders will adhere to the trim-to length listed in the manuals, and this is my recommendation. Just be aware that once in awhile a case will pop up that is a few thousandths under, this should not effect anything, except have a miniscule chance of of reducing accuracy, but with most sporting firearms the difference won't be noticed.