May 31st, 2019

Eyeball Your Brass — How to Diagnose Flawed Cases

Case Diagnostics 101 Sierra Bullets .223 Rem 5.56 brass cartridge safety

Ever wondered what caused a particular bulge or marking on a case? And more importantly, does the issue make the case unsafe for further use? Sierra Bullets Ballistic Technician Duane Siercks offers some insight into various issues and their causes in this article from the Sierra Blog.

Incipient Case-Head Separation
This is a Winchester .308 Win case that has a real issue. This case has a very obvious incipient case head separation in the process of becoming a complete failure.

Sierra Case reloading pressure safety inspection

This is most commonly caused by over-sizing the case causing there to be excess headspace on the case. After a few firings and subsequent re-sizing, this case is just about ready to come completely apart. Proper die adjustment is certainly a requirement here. Of course this case is not safe to reuse.

Excessive Pressure (Load Too Hot)
If you will notice in the picture of the case rim, there are two pressure signs to notice. First, look at the primer. It is basically flattened to about the max of what could be considered safe. If this was the only pressure sign noted, I would probably be fine with this load, but would constantly keep an eye on it especially if I was going to use this load in warmer temperatures. This load could easily cross into the “excess pressure” realm very quickly.

Sierra Case reloading pressure safety inspection

There is another sign of pressure that we cannot ignore. If you’ll notice, there is an ejector mark apparent that is located over the “R” of the R-P headstamp. This absolutely tells us that this load would not have been in the safe pressure range. If there were any of these rounds loaded, they should not be fired and should be dis-assembled. This case should not be reloaded.

Split Case-Neck
Here we have an R-P .22-250 case that has died the death. Everything looks fine with this case except the neck is split. This case must be tossed.

Sierra Case reloading pressure safety inspection

A split neck is a normal occurrence that you must watch for. It is caused by work-hardening of the brass. Brass cases get harder with age and use. Brand new cases that are stored for a period of time can become hard enough that they will split like this case within one to two firings. I have had new factory loads do the same thing. Then as we resize and fire these cases repeatedly, they tend to get harder and harder. Eventually they will split. The life of the case can be extended by careful annealing practices. This is an issue that would need to be addressed in an article by itself. Of course this case is no longer usable.

In the classes that I teach, I try to use examples like this to let the students see what they should be looking for. As always, if we can assist you, whether you are new to reloading or very experienced, contact us here at Sierra Bullets by phone at 1-800-223-8799 or by email at sierra@sierrabullets.com.

Dented Case Body
Here we have a Lake City 7.62×51 (.308 Win.) case with two heavy marks/dents in the case body.

Sierra Case reloading pressure safety inspection

This one may be a bit of a mystery. It appears as if this case may have been caught in the action of a semi-auto rifle when the firearm jammed or the case failed to clear during the cycling process. I probably would not reload this case just to prevent any feeding problems. This also appeared to be a factory loaded round and I don’t really see any pressure issues or damage to the case.

CLICK HERE for MORE .223 Rem Case Examples in Sierra Blog

It is very important to observe and inspect your cases before each reloading. After awhile it becomes second nature to notice the little things. Never get complacent as you become more familiar with the reloading process. If ever in doubt, call Sierra’s Techs at 1-800-223-8799.

Sierra Bullets Case Diagnostics Blog

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 1 Comment »
March 2nd, 2018

Add 3-Way Case Mouth Cutter to Your Forster Trimmer

three-way three in one cutter

We know many of you guys have a Forster case trimmer (hand lathe) sitting on your reloading bench. This tool does a good job of trimming cases to length. But did you know that an inexpensive accessory will allow your Forster case trimmer to chamfer while it cuts? Here’s the skinny on the 3-way head for the Forster case trimmer.

Tool Cuts Brass to Length, and Chamfers Inside and Outside
Forster’s 3-in-1 Carbide Case Mouth Cutter works with all existing Forster case trimmers. This unit does three jobs at the same time. It trims the case to length, it puts a 14-degree chamfer on the INSIDE of the neck, AND (last but not least), it cuts a 30-degree chamfer on the OUTSIDE of the neck. It does this all quickly and efficiently — in a matter of a few seconds. We tested the new tool ourselves on a few cases. The tool is solid and well made. The carbide cutting tips do perform a very clean cut. Be aware, however, if you have turned your necks already, you may have to reset the blade positions before you start trimming your brass.

Forster’s CFO, Robert Ruch, demonstrates the 3-in-1 case trimming/chamfering tool in the video above. As you can see, the tool turns very smoothly (no chatter). The actual cutting time, per case, is just a few seconds. The tool has an MSRP of $88.00, but it sells for around $65.00 to $70.00 at major vendors. Forster’s 3-in-1 Carbide cutting tool works with all existing Forster case trimmers and other hand lathes with a .490″ shaft diameter. The unit fits over the cutter shaft and secures with one set screw. The 3-in-1 cutter is available for five (5) calibers: .224, .243 (6mm), .264 (6.5mm), .284 (7mm), and .308.

Forster Case neck trimmer chamferer

Permalink - Videos, Reloading 7 Comments »
June 9th, 2013

Reverse Your Rocket Tool for a Smoother Inside Neck Chamfer

Want smoother chamfers on your case-mouths? Here’s a simple tip that can: 1) remove the sharp edge left by chamfering blades; and, 2) create a smoother entry for your bullets. Smoothing the inside chamfer can avoid nicks on your bullet jackets, and can also make bullet seating more consistent.

If you are using a 45° rocket tool on newly-trimmed brass, start your inside chamfer with two or three turns in the normal cutting direction. Keep the tool centered, and use light-to-moderate pressure — you don’t need to remove a lot of brass. After your cutting turns (which should reveal a shiny chamfer line), take out the tool, inspect the neck and remove any small brass chips or shavings.

Now here’s the secret — put your tool back in the neck and go in the reverse direction for a couple partial turns. Again, be sure to keep the tool centered and use a light touch. The reverse rotation of the rocket tool inside the case mouth will burnish and smooth the chamfer. Next you can make a quick spin with some fine steel wool held in your fingers. Don’t grind away — you do NOT want to get rid of all the carbon in the neck. As a last step we run a hand-held nylon brush in the neck for 2-3 quick passes to further smooth out the chamfer and remove any residue from the steel wool.

Accurateshooter.com Neck Case Chamfer Brass prep

We think, if you use this procedure, your will find that your bullets seat more smoothly and consistently. That can improve accuracy and help avoid mysterious fliers.

Accurateshooter.com Neck Case Chamfer Brass prepYou can use this same technique even if you prefer a sharper angle chamfer tool for your initial inside-neck chamfering operation. Reverse your tool gently a couple turns to burnish and smooth the cut. And always remove brass chips and shavings before you run the tool backwards (in the non-cutting direction).

Don’t Forget to Smooth the Outside Chamfer Too
You can also use the backwards rotation trick on outside chamfers to smooth and soften the sharp edge. A little steel wool, applied judiciously, can help here. If you are chamfering a large number of cases after trimming, you may want to tumble the brass in corn-cob or walnut media after the chamfering procedure. Tumbling further smooths the chamfer. You want a nice, smooth chamfer with no burrs or sharp edges.

Permalink Bullets, Brass, Ammo, Reloading 4 Comments »