Case Length Questions/Concerns


PDA






average_shooter
November 22, 2007, 12:13 AM
Ok, so I am just starting to get into reloading rifle. So far I've been reloading .45ACP and haven't worried about case length and haven't had a problem. But now with .223 Rem. I've been looking into case length issues. I'm using a Speer manual and have some questions regarding case length.

So for the bullet I'm using (.224 dia., 55gr. FMJBT with cannalure) Speer lists overall cartridge length as 2.215 inches. Max. case length is listed as 1.760 inches (IIRC). My understanding is that if I'm using a bullet with a cannalure I should seat the cannalure to the edge of the case mouth, not deeper.

The problem/concern; If I do that with a case length of 1.760" I'm over COL for the load. If I trim the case back to where I can seat the bullet where the cannalure is aligned with the case mouth and with a COL of 2.215, the case length ends up being 1.715" which looks to be way too short.

What say the experts? :confused:

If you enjoyed reading about "Case Length Questions/Concerns" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
Jim Watson
November 22, 2007, 12:33 AM
I say the cannelure does not mean squat unless you are crimping bullets for use in a machine gun or tube magazine. Seat to book OAL, seat to just run through the magazine, or seat to a reasonable distance off the rifling.

esheato
November 22, 2007, 12:36 AM
Depending on the gun type you're using (bolt vs semi), the limfac is magazine length (semi) or chamber (bolt).

Ignore the cannelure unless you're loading for a semi-auto and you have concerns regarding bullet setback.

Ed

average_shooter
November 22, 2007, 12:40 AM
I should have mentioned, I am in fact loading for a semi-auto. Which is why I'm guessing I'll need to crimp on the cannalure.

steve4102
November 22, 2007, 01:02 AM
The overall length of a published load doesnt mean squat. They did not use "Your" rifle to develop their data.

Seat your bullets to the cannelure and crimp as long as they are not to long for "Your" chamber. Measure your chamber with your selected bullet. As long as you stay off the lands and your rounds fit into the mag you are good to go.. Just remember to start low and work up.

esheato
November 22, 2007, 06:21 AM
In fact, just because you have a semi-auto doesn't mean you require a crimp. If you have enough neck tension from sizing and the bullet doesn't set back upon recoil, then you have no worries.

Measure a cartridge. Put it at the bottom of a mag. Put 5-10 rounds on top of it. Fire all but the last one. Re-measure the cartridge. If there is significant setback, a crimp would most likely be in order. Of course there are other ways to increase the hold on the bullet also. If you're using a neck sizing die with a bushing, you can drop down a thousand or two to increase the tension.

Lastly, where are you measuring from? Ogive or bullet tip? You should be measuring from the ogive as bullet tips do not provide accurate measurements.

The tool used to measure OAL from the ogive are called comparators. (http://www.sinclairintl.com/cgi-bin/category.cgi?category=RESDTCO&type=store)

Ed

RecoilRob
November 22, 2007, 12:51 PM
2.215 is really short. Most likely, they published this as a minimum OAL to keep you safe..pressure wise..as long as you don't go below it.

If your cases are within the Min-Max trim length and you seat to the cannelure, you will likely be under the 2.260 Max OAL and the rounds will fit in the magazine...which is all that really matters. Never seen an autoloader that had such a short throat that any bullet that can be magazine fed got into problems.

rcmodel
November 22, 2007, 01:20 PM
and the bullet doesn't set back upon recoil,Bullets don't set back from recoil in a .223 semi-auto.

They set back from hitting the feed ramp on the way into the chamber.

As for the original question, you are thinking too much!
My Speer #13 manual has no mention of a OAL of 2.215" in .223 Remington.
They show 2.260" as max OAL with any bullet they make. That is so they will fit any & all standard magazines & actions the .223 is used in.

If you are reloading for an AR-15, Mini-14, etc.,there is no need to fiddle & diddle with measuring lands, ogives, etc.
If it was me, I would trim all the cases to the recommended 1.750" trim length.
Then seat the 55 grain bullets to the cannelure and crimp them lightly.

I think you will find that any .224 dia. bullet with a cannelure will seat to the proper length to work through standard semi-auto magazines.
The bullet manufacture put the cannelure on the bullet in the proper place, I betcha!

http://i81.photobucket.com/albums/j219/rcmodel/KTOG/1224.gif
rcmodel

Walkalong
November 22, 2007, 04:12 PM
If you are reloading for an AR-15, Mini-14, etc.,there is no need to fiddle & diddle with measuring lands, ogives, etc.
If it was me, I would trim all the cases to the recommended 1.750" trim length.
Then seat the 55 grain bullets to the cannelure and crimp them lightly.
Ditto. That is what I do for cheap blasting/plinking ammo.

If you use a Taper Crimp die such as the Redding (http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=726501&t=11082005) for .223 your case length is not quite as critical either. I do it both ways. Roll and Taper. Can't really prove much difference either way with the cheap bulk 55 grainers.

If you enjoyed reading about "Case Length Questions/Concerns" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!