To trim or not to trim

[Mikee Loxxer]

I am in the process reloading some .308 Win cases for my DSA SA58. The question I have concerns whether or not I should trim the cases I am using. Keep in mind these cases are a mix of Lake City, CAVIM, IMI, and Hirtenberger. After full length resizing last night I decided to check the length of each of the cases with my caliper to see if they were longer than the 2.015 inches specified by the Lee reloading manual.

Only two of the 49 cases were at the 2.015" spec. Other ranged from around 2.022" to nearly 2.040". Should I invest in a case trimmer and bring them down to 2.015"? I am leaning in that direction but felt that I should ask the experienced reloaders on this board.

 

[The Bushmaster]

Lyman #48th edition shows "Trim to length" of 2.005. And a maximum of 2.015. I would trim them to 2.010. Load them. After you have fired them and cleaned and resized them, check them again and see if they changed. If not leave them at 2.010 to 2.015.

 

[Mikee Loxxer]

Thanks Bushmaster, I appreciate the input.

 

[P0832177]

The trimming is needed.
A case that is too long with a loaded round could suffer a spike in pressure. The reasoning is that long case neck would squeeze the bullet tighter then it already is becaue it would jam into the lands. This would increase the pressure. Now if you had a chamber cast you could really make the proper trimming ajustment.

 

[Mikee Loxxer]

A chamber cast may be something useful to pursue. Would one use wax or a special lead alloy? And if it is the alloy what kind of special equipment would be needed?

 

[USSR]

Mikee,

While cases have to be trimmed when they become excessively long, there is no one "specific" OAL that they must be trimmed to. The important thing is that they are all trimmed to the same length. I typically trim them all to about the OAL of my shortest case, assuming that it is not shorter than the "trim to length" shown in the reloading manual.

Don

 

[Matt-man]

A chamber cast may be something useful to pursue. Would one use wax or a special lead alloy? And if it is the alloy what kind of special equipment would be needed?

It's usually an alloy called Cerrosafe. I've never used it, but I've seen it in the catalogs.

If all you want to know is your max case length, an easier option is to use a chamber length gauge like these from Midway. You will need some way to trim cases before you can use the gauges, as they require a case trimmed shorter than spec in order to be used.

 

[TooTaxed]

PO832177 has it nailed.

I find I must trim virtually all once-fired rifle cases...and most new ones also!...from .223 NATO to .30-06. They vary in length and should be brought to the same length.

I haven't had that problem with pistol cases except .45 Colt, some of which is made of rather thin brass...found some folds at the canellure after crimping on some cases.

 

[BigBob3006]

Mikee,
I prefer to have as long a neck as possible on a case in order to insure a firm grip on the bullet. I have never found a rifle chamber that didn't have a neck much longer than S.A.A.M.I. specs. Sinclair offers a gage they call a case length gage that cost a little over $6.00. If the directions are followed, it is possible, and easy, exactly what the length of your rifle chamber is. My Rem. M-700 BDL in .308 Win has a neck that measures 2.039". I trim my cases to 2.035". This allows me to seat my bullets closer to the lands. Don't use longer than S.A.A.M.I. specs cases unless you do determine the length of your rifle chamber.

 

[TooTaxed]

BigBob, your suggestion seems good.

Now, who is "Sinclair"? Dealer or manufacturer, and where did you find ther stuff?

 

[target4fun]

I would invest in a case trimmer. I shoot out of my m1a as well as my bolt gun in 308. I guage all of mine, if its 2.015 then I set it aside to trim, I advice the same. If your over maximum specs your result will be not very accurate or not as accurate as it can be, more importantly it will not be as safe they set these specs to cover there @$$ and keep you safe.... I would hope you would keep your self safe.

 

[The Bushmaster]

Hey Bigbob3006...I have one. a chamber that is not very much over maximum case length. If I don't trim to keep my .30-06 cases at or less then maximum length I have a problem chambering (closing the bolt). .005 +/- .001 over and I start having problems. Proper case length is very important for several reasons as stated above. And if you crimp it is best to have every case in that particular batch the same length or within +/- .002. At least that is my allowed tolerence for both rifle and revolver cases that require crimping.

 

[ball3006]

Buy a Lee case trimmer.....

they are cheap and work well. The only drawback is you cannot adjust the case trim length.........chris3

 

[WayneConrad]

I second Ball's suggestion to get the Lee trimmer. Cheap as dirt, and pretty quick. Get the ball-handled cutter. Your hands will be pleased. And get a cordless screwdriver or variable speed drill on your bench. Chuck the shell holder into the tool, put a shell in the holder, start it spinning, press the cutter & guide into the shell, and watch the brass shavings peel off. Then a quick touch with the champher/deburr tool, a quick press of fine steel wool, and remove the shell from the shell holder.

 

[Matt Dillon]

I use that Lee case trimmer with a cordless drill, and go through quite a number of cases in one evening, while watching the TV in the air conditioning. I trim ALL cases, from the small .32ACP through all my rifle cases. I never have trouble chambering, and I have the assurance that all my brass is uniform.

 

[BigBob3006]

too taxed,

I thought the whole world knew about Sinclait International. This is their web site www.sinclairintl.com I've bought a lot of things from them and have yet too find nicer people. If Sinclair sells it, it is top quality. Many of the items they sell, they make. Give them a look, I think you'll like them. For those looking for case trimmers, I've tried several and am now using a Forester. I like it. Wilson may be a better on, but Forester will do a good job for you.

 

[moredes]

RCBS X-Die

error

 

[moredes]

RCBS X-Die

Nobody's mentioned it, so I will. PO832117 is right, ya gotta trim cases to avoid spiking your pressures. That's the only real reason to do it from a "safety" point of view. Another reason shooters do it is to standardize all the cases to one length for the sake of accuracy.

However, in your gas gun, it probably doesn't make much difference in accuracy that the cases are all the same length; not being presumptious about the inherent accuracy of your particular rifle nor your shooting skills, but some gas guns just don't benefit as much from strict trimming regimens as others might.

I'd suggest buying an RCBS X-die before you trim the first time. If you use the X-die to resize your cases, you'll never have to trim again after the first time, for the entire life of the case. Conduct a search on "X-die" or go to the RCBS website for a primer on its' function.

For $35 or whatever I paid, I trim once to an OAL of 1.995" and have never trimmed again, through seven (!) reloads in an M1A. That number of case reloads is unheard of, for a gas .308; they're still going strong... I check each case individually for incipient head-separation. The cases have stopped stretching at 2.007-2.009". Whenever they indicate they're about to split, I'll trash the whole lot.