Lake city brass trim to length issue

[bddc2012]

I have several 1,000s of Lake City .223 cases to trim to length.

I am using a case trimmer ( well known brand ) that uses the shoulder as the point to trim off of.

The trimming started off great quick & accurate now after 1,550 + cases the OAL is all over the place running from
the 1.750 OAL I setup to then ranges wildly from 1.70 to 1.40.

When I use a Lyman case trimmer I am good.

Any ideas to help this issue are most welcome.

 

[stool]

check for brass build up in side at the shoulder section of the cutter

 

[bddc2012]

Thanks for the reply I will monitor for this.

 

[stool]

hmmm i have it backwards...you have short brass.....
how well was it sized prior to trim ??
a build up of brass will make it longer...unless you started that way...or their tool has worn.

 

[jonbearman]

I must assume you are using a gracey or something like it. If you are getting weird lengths suddenly, the cutter itself may have moved in and the set screws are loosening up or the lock for the bushing is loose and it gradually screwed in towards the cutter.

 

[bigedp51]

Make sure the set screw didn't loosen on the the cutter, it might be moving, there is also a video on cleaning the brass chips at their website. I use a small stiff brush and canned air to blow the unit clean and measure each case after it is trimmed to stay ahead of the problem.

oops, jonbearman has faster fingers than I have, I only have two dyslexic fingers that know the Columbus method of typing...........discover the key and land on it.

 

[savagedasher]

Lake city brass May of ben fired in many of different guns with all different chambers. If the base to shoulder is all the same .The trimmer you are using will work fine. I would check base to shoulder. Larry

 

[navyrad8r]

something came loose? or you sneezed and shoved it into the trimmer extra hard!
never trim when you are mad at the kids etc... ;D
cheers,
doc

 

[jlow]

Lake city brass May of ben fired in many of different guns with all different chambers. If the base to shoulder is all the same .The trimmer you are using will work fine. I would check base to shoulder. Larry

That's correct. If you expect identical OAL, then your headspace must also be the same because as you say you are indexing off the shoulders. If you have not bumped the shoulders so that the headspace is the same, you cannot expect identical OAL

 

[MGYSGT]

My trimmer was giving the same type of results. Turned out the expander ball was pulling the shoulder back out when full length resizing and messing up the end results when trimming.

 

[bddc2012]

I have followed the suggestions offered here cleaned the trimmer,full length sized all cases,checked set screws for tightness,did not trim while mad at the kids,did not sneeze while setting up the trimmer and am still getting varying OAL.
the only idea I have left to do is resize all cases and sort by length before trimming????

 

[stool]

did you do a spot check on 25 or so resized cases ?? to the shoulder are they the same ??

 

[bddc2012]

I spot check every 20-25 cases I switched to a different batch of LC cases and the issues have gone away.
If the expander ball is pulling the case out after resizing how do you fix that?
Thanks

 

[stool]

i have not used expander balls in years...bushing dies.

 

[averh2o]

lube the inside of the case neck and the stretching issue should go away

 

[gotcha]

If you're using an expander ball type die a Carbide sizing button might help also. Best advice, Trim AFTER fire forming.

 

[bddc2012]

Thanks for all the help men.

 

[bddc2012]

Update,
I followed the advice given by the responders in this forum and have some takeaways from my experience.
Lake City once fired military brass is WORK.
I am using the Worlds Finest Trimmer (WFT) to trim my cases which was working fine on about 1,800 LC cases until I ran into a batch of the same that was giving me fits.I called and talked to Dale H at WFT he gave some suggestions which did not help me so I sent the .223 trimmer back to him for inspection as advised to by himdid some root cause anaylisis, he polished the trimmer die and replaced the cutting bit.
I recieved the trimmer back but the same issue of inconsistent trim to length.
I did some root cause analysis to determine the solution.
I found that by switching to a smaller thickness of shell holder in this case .003 thinner and resizing the cases the WFT performs as expected and is very accurate +- .001 from my experience.What a difference a few .000 make. Thanks to you all and to Dale H at Little Crow Gunworks.

 

[artbosco]

I have several 1,000s of Lake City .223 cases to trim to length.

I am using a case trimmer ( well known brand ) that uses the shoulder as the point to trim off of.

The trimming started off great quick & accurate now after 1,550 + cases the OAL is all over the place running from
the 1.750 OAL I setup to then ranges wildly from 1.70 to 1.40.

When I use a Lyman case trimmer I am good.

Any ideas to help this issue are most welcome.

Never index off the shoulder. Index off the bottom of the case.

What are the odds, that the dimensions on all 1550+ cases are identical, to the last .001" or .0001", from the shoulder to the bottom of the case? ???

 

[fguffey]

The trimming started off great quick & accurate now after 1,550 + cases the OAL is all over the place running from
the 1.750 OAL I setup to then ranges wildly from 1.70 to 1.40.

The length of the case from the mouth of the case to the head of the case? I have been informed there is only one case length according to SAAMI. I have Wilson case gages, Wilson case gages measure a case from the head of the case to a datum and from the datum to the mouth of the case, that gives me three lengths.

Keeping up with lengths, to use a trimmer that sets-up on the shoulder requires a reloader to keep up with the length of the chamber from the datum/shoulder to the bolt face. I have one rifles that has an additional .016" chamber length between the shoulder of the chamber to the bolt face. When determining case length and neck length I have to add .014" to the case between the shoulder and case head. I do not change the length of the neck from the shoulder of the case to the case mouth.

Point? When a reloader uses a trimmer that sets upon the shoulder with total disregard for chamber length from the datum to the bolt face is going through the motions of trimming, when finished they will be required to go back and trim for case length from the end of the neck to the case head.

Trimming after sizing. It is assumed the case length from the shoulder to the head of the case is correct, if it is then setting up on the shoulder in a trimmer should leave the cases close in length from the mouth of the case to the head of the case.

F. Guffey