Case neck trimming questions

I made a similar deal once, thought it was my own idea, ha-ha. For the $5 or whatever, the ones from Sinclair are way easier to use. I can't even remember what the rifle was, but I found myself not having a chamber length gauge to fit once and made one out of a wood dowel in the Sinclair model. Just chucked the dowel in a drill motor and filed it to shape and size. That was actually way easier to make than the split case and worked better too.

Have modified all my Sinclair gauges the same way to fit my tight neck chambers. Takes only a few seconds.


Originally Posted By: B23
I have always been told you want your case neck length about 10 thou shorter than actual chamber length, anyone have any thoughts on where to set trim length???

I'm still waiting for any of mine to get that long. Primer pockets have always loosened up first. Or the barrel wore out. Starting with a longer parent case, I shoot for .010 and they usually shorten up a bit more after fireforming and I've never had to trim any of those ever again. YMMV though. My loading practices work/move brass a very minimal amount.

- DAA
 
Originally Posted By: Dultimatpredator
I always find a load that will shoot a nice little cloverleaf when I ladder test as long as I do my part. I don’t know if trimming my case necks is a factor in this though?

I realize that if a case neck varies in length it could cause more or less neck tension.

Has anyone tested trimmed cases VS various lengths VS groupings?

Thoughts?

At closer ranges you don't see much changes, You can still get great accuracy and precision shooting groups at 100 yards even with mild powder charge variations.
You start to see the difference at ranges, like a fella stated above, depends on what you are doing, plinking, hunting close, or doing some LR work... The further you stretch out your shots, more variation you see regarding velocity due to tension differences. To guys shooting Deer 400 and in, it may not make a bit of difference, to guys trying to shoot groups half a mile or further, it plays a part.
 
Originally Posted By: DAAI made a similar deal once, thought it was my own idea, ha-ha. For the $5 or whatever, the ones from Sinclair are way easier to use. I can't even remember what the rifle was, but I found myself not having a chamber length gauge to fit once and made one out of a wood dowel in the Sinclair model. Just chucked the dowel in a drill motor and filed it to shape and size. That was actually way easier to make than the split case and worked better too.

Have modified all my Sinclair gauges the same way to fit my tight neck chambers. Takes only a few seconds.


Originally Posted By: B23
I have always been told you want your case neck length about 10 thou shorter than actual chamber length, anyone have any thoughts on where to set trim length???

I'm still waiting for any of mine to get that long. Primer pockets have always loosened up first. Or the barrel wore out. Starting with a longer parent case, I shoot for .010 and they usually shorten up a bit more after fireforming and I've never had to trim any of those ever again. YMMV though. My loading practices work/move brass a very minimal amount.

- DAA the fact reloading manuals dont mention these inserts is criminal. I do way less trimming now days
 
Originally Posted By: DAAOriginally Posted By: JMetteMike B what tool could you use to measure your neck length in the chamber? Just curious


I've been using these for a long time. Since before Sinclair had a website, ha-ha!

Chamber%20Length%20Gage.gif.jpg


I haven't trimmed a working case in twenty years.

- DAA


I loath trimming brass, so I'll definitely be adding these to my reloading tool case. Thanks for sharing.
 
DAA .. Thnks for the info. thats good to know. i've reloaded for years and wasn't aware of this tool.. appreciate it.
 
Buy the chamber length gauges...you are in for a shock on factory rifles.


I trim cases only when necessary. If you think that your cases are too long, smoke the end of the case mouth with a candle or cigarette lighter. Now chamber the round, carefully extract. Look at the end of the case. If there is a bright spot on the end of the case mouth, you know that it is touching the end of the chamber. The Sinclair gauges are in a plus in that you have a hard number to work with.

Certain cases grow a lot, some do not, and the 220 Swift is the worst offender.

I trim after I have full length sized, and full length sizing causes cases to grow more than neck sizing. For this reason, I have shoulder bump dies from Forster in quite a few calibers. Many do not know that the standard Forester Neck sizing dies can be used to bump shoulders, but their new shoulder bump dies are very effective with the addition of selecting the dia. bushing that you like to size to, and bump your necks at the same time.


In a lot of cases, all you will ever do is bump the shoulders back and NEVER full length size a case or rarely full length size a case.
 
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