NEVER TRIM more than 4x.....

[243BR]

Thin enough to cause case head separation??

I have had case head separation after a few trimmings. It was 6BRX brass that I had fireformed. That may have caused it to be weaker to begin with.

 

[Bart B.]

Case stretching happens due to the amount of head clearance, and your head clearance (upon firing) corresponds to your amount of shoulder bump.

Except when the case shoulder is set back from firing pin impact before pressure reaches maximum. Then there's more head clearance.

 

[riflewoman]

Case brass at the pressure ring work hardens before any other area.

Regarding fired cases from 7.62 NATO semiautomatic service rifles used in competition, nobody consistently shooting the top scores reloaded fired brass from them. Case heads were too much out of square. Shots strung between 7 and 1 o'clock on target; right angles to bolt lugs in battery. Their bolt faces were never squared up.

I gave away thousands of once fired M118 match cases to civilian shooters; their tax dollars paid for them.

Well, I got these shooting reloads in my M1A and I never had stringing.

 

[Bart B.]

View attachment 1078170 View attachment 1078169

Well, I got these shooting reloads in my M1A and I never had stringing.

Did your ammo test well under 4 inches for 20 shots at 600?

One doesn't need consistent top scores to get those awards. 99th in the Pres 100 and 5 bronze legs at the low end.

Some Distinguished badges were awarded to people who never fired in a leg match.

 

[jepp2]

If you want a accurate way to measure case thinning then buy a RCBS case mastering gauge.

Will do a very good job.

Or just use the bent paper clip and toss the case when you can feel the tip catch on the thinned area.

 

[riflewoman]

Did your ammo test well under 4 inches for 20 shots at 600?

One doesn't need consistent top scores to get those awards. 99th in the Pres 100 and 5 bronze legs at the low end.

Some Distinguished badges were awarded to people who never fired in a leg match.

I don’t know how it grouped in my M1A, but the ammo loaded for my M1A groups 3/4 inch at 100 out of my bolt rifle 20 years after it was loaded. I shot 67th on the 100 and my first leg was at Perry and was a Gold leg .

 

[savagedasher]

Trimming 4 times sounds like painting wit a large brush
lol

 

[MQ1]

Case brass at the pressure ring work hardens before any other area.

Regarding fired cases from 7.62 NATO semiautomatic service rifles used in competition, nobody consistently shooting the top scores reloaded fired brass from them. Case heads were too much out of square. Shots strung between 7 and 1 o'clock on target; right angles to bolt lugs in battery. Their bolt faces were never squared up.

I gave away thousands of once fired M118 match cases to civilian shooters; their tax dollars paid for them.

Bart,

I’m curious....do you know if the same be said about 30/06 brass fired in a Garand?

MQ1

 

[Bart B.]

Bart, I’m curious....do you know if the same be said about 30/06 brass fired in a Garand?

Yes, because their bolts were never squared up.

Might be hard to see as Garands in 30-06 were never as accurate.

 

[Rsadams]

Just 2 cents here but I check rifle cases everytime with the bent paper clip method on my case master just to be safe... There's no reason to take chances , if you even think something is wrong chunk them.... I trim my brass to all one length every time I load them , at about five , I scrap bucket them because I don't anneal.... If I need more brass I just go buy a bag or box... I am not shooting competition exept against myself so I am not useing $100 a box brass though...

 

[varget204]

I think it depends on caliber,brand of case,pressure etc. I shoot thousands of 204 ruger rounds,Some cases loaded 20-25 times or more since 2009, I trim about every 1-2 times fired, or when OAL grows .002-.003,Norma,Nosler cases usually start .003-.006 shorter than 204 ruger -1.840 trim length , Some cases not much,Usually neck sized cases. I FL resize almost every thing now;that's whats most accurate out of my rifles.I know i've had cases trimmed 10-15 times.Replaced 2 barrels ;now i trim to 1.845- I throw them away when neck slits,or at start case head separation. In last 10 years I have shot over 15000 rounds, I took large paper clip,pounded 1 end flat to about .015,filed it, tapered it about .100 to diameter of clip, bent it 90 degrees so about .080 sticks out, I check every case for separation { usually get a ring inside case about 1/2" above base.Had 2 in last 10 years separate. 1 while extracting,case separated on feed ramp,lucky, the other separated by hand while prepping cases.Have had roughly 40-50 cases split or show signs of separation,it's easy to feel groove start to form.75 persent of start of case separation have been w/ recent new Hornady cases.In 204 ruger they are about 5-10 grains lighter case than old ones.I've had a few after only 2-4 fireings.

 

[K22]

I believe the trimming guideline published in the Lyman Manual is a generalized "rule of thumb" for indirectly indicating the maximum amount of case working (i.e. expanding and contracting from repeated firings and sizing). And one should keep track of the amount of trimmings which can be useful in evaluating you sizing effectiveness.

By properly sizing my cases with a .001 to .002 shoulder set back (bolt rifles) I rarely if ever need to trim more than four times before neck splits or other wear defects begin to appear that will cause me to retire that set of cases. By measuring the amount of case stretch of a fired case in a case gauge tool you will get an idea how much expansion you are experiencing and whether it is excessive and if a die adjustment is necessary. Over sizing can lead to excessive case stretch which is undesirable and can be unsafe.

No matter which method of sizing you use you should always inspect your cases at each reloading for any signs of incipient head separation and retire them if found.

 

[JimSC]

No matter which method of sizing you use you should always inspect your cases at each reloading for any signs of incipient head separation and retire them if found.

I agree. Right now my habit is to buy 200 brass with each new barrel (.260 Rem) and shoot them round robin 10 times then replace barrel and brass but I still look for loose primer pockets and weakened brass since I had a head separation at the 5th firing once. non catastrophic thankfully. You have be too careful with stuff. We all know people who have had or seen some bad ones

 

[MikeMcCasland]

I just run them in the giraud after every firing, and look for the ring in the body of the case; seems to work for me.

 

[Dgd6mm]

I just run them in the giraud after every firing, and look for the ring in the body of the case; seems to work for me.

Mike, your not the first one that I know does this (trim after every firing).

 

[jlow]

Mike, your not the first one that I know does this (trim after every firing).

Same as me. If you have the Giraud, why not? It's easy, painless, and gives you consistency.

 

[jlow]

FWIW, that thinning ring when it does show for regular calibers is almost always due to someone bumping the shoulders too much....

 

[Dans40X]

And Lyman has drawn how many jackets to come to those conclusions....NONE.

I'd use a Lyman reloading manual to fire up the wood stove....once!

 

[Brians356]

Handloader A trims cases after every firing. Handloader B trims cases only when they have stretched .005" over initial trim length. The futility of stipulating an arbitrary, universal maximum "safe" number of trims is thus revealed. [mic drop]
-

 

[BoydAllen]

Case growth after the first firing is tied to the difference between the die's dimensions and those of the chamber, as well as how carefully the die is set, and factors that dictate how the sized case must fit the chamber. Semiautomatics require more case clearance at the shoulder and in diameter than bolt rifles, and so their cases can be expected to grow, and thin more than the same case would, sized with a closely fitted die, set for minimal shoulder bump.

How does that Lyman manual tell you to set a FL die?

For those that find themselves in a quandary because of short new case datum to head length, you could always go the false shoulder route for the first firing.

Manuals have basic reloading instructions, and as we gain experience and learn, our approaches tend to become more customized to individual reloading situations...or at least they should.

Back in the day I had a .220 Swift, and the only dies that I had were RCBS with the typical One piece, size the crap out of the case FL die. Even though I paid close attention to how I set the die, I was having to trim a lot. Back then RCBS would lap out the body of a die if you sent them a case or two and the die. I had that done, and case growth was cut in half. Their lapping was more conservative than I would have liked, but I was glad for the improvement.

Some time after that I got my first 6PPC and in the course of doing some product writing ended up with a Harrell Vari-base die that does not size the diameter of the front of the case body. It has threaded inserts to be able to vary the sizing at the back of the case, which I generally choose to give me about .0005, and it can be set for shoulder bump just like an ordinary FL die. Regular Wilson style bushings are used to size the necks. With this die set up properly, probably because the front of the brass is not over thick, sized cases can be chambered without any feeling of tightness, and because the cases see so little body sizing, the amount of growth is miniscule.