Trim-To Length

[Jayhawker]

The answer to this may be so simple that I'm not seeing the forest for the trees. What should I use as trim-to length for 6x47 brass? Since it's still "officially" a wildcat cartridge, there's no SAAMI specs. Thought I'd just measure them all and go with the shortest ones but wanted to check with someone who knows.

 

[357Mag]

JayHawker -

Howdy !

An idle thought.... you could have Wilson, Redding or other vendor make you a custom case length gage.
Really, more of a neck length gage; when trim-to-length is what you're looking for.

IMHO - These guys would have a 6X47 spec already in-mind, and the gage design is easy-as-pie to use.


With regards,
357Mag

 

[ar10ar15man]

measure the depth of your NECK in teh chamber...and back off what you are comfortable with.
cut real short and trim less often, cut them long and trim nearly evey use.
the short cut can lead to carbon build up in the neck of the chamber.
to measure the neck in the chamber buy a sinclair neck measuring button/tool for all of 7 or 8 bucks, sacrifice one case to use as a tool holder and its that simple......

 

[Jayhawker]

Thanks for the replies. The chamber length gauges look like the hot ticket and what's best, they're not expensive. I understand how they work but once you establish chamber length, how much less do you trim the brass?

 

[itchyTF]

FWIW, I trim .010 less than the chamber. Whether you'll have to trim often (every shot?) depends on how much the case stretches. A few of mine (6mm-250, 6x47L & .243AI) don't stretch that much but I can't tell you offhand how many firings before trimming.

 

[NorCalMikie]

Also depends on what type of sizer die you're using. Full length will make for more trimming. Neck button pulls the neck longer over time.
Neck size and shoulder bump dies (Forster) keep the case and neck at the same size. May not have to trim for many firings. 25+ on 6BR cases and they're still the same length. 8)

 

[SS427]

Sinclair makes a plug you can put into an empty case that is trimmed really short. Chamber the case and the plug will engage the extreme end of the neck area of the chamber and then push back into the case. Measure that and you know the maximum length your cases can be. Trim accordingly.

http://www.sinclairintl.com/reloading-equipment/measuring-tools/case-gauges-headspace-tools/sinclair-chamber-length-gage-prod32925.aspx

 

[Catfish]

The only way to know to know the exact lenth of the chamber is to have a chamber cast made. From that you can deside how much expancation you will be satisfied with and go from there.

 

[SmokinJoe]

IMO, the Sinclair plug gauging method is the best since you are actually measuring from the boltface to the end of the chamber. An important part of this setup is making the end diameter of the plug about the same as a fired case, which may require some modification since many of us have chambers with smaller neck diameters than SAAMI. That is easy to do by chucking the Sinclair plug in a cordless drill & working it down carefully with a file, checking often so you don't overdo it. I check the chamber OAL on all my rifles, both custom & factory, and record that dimension along with neck diameter, bullet seating lengths, etc. It can be an eye opener as far as variations go; some customs are very tight, some factory chambers can be overly long. As far as trim-to length, I have been under the impression that .015" shorter than chamber OAL was the accepted amount for as long as I can remember.