Trouble with my 223 OAL, any ideas?


PDA






Deavis
December 27, 2008, 05:14 PM
Having some trouble getting the OAL of my 223 rifle rounds to be consistent. I know why I don't like loading rifle as much as pistol!

Here is what I'm doing.

Trim Setup on a 650XL using Uniquetek's toolhead clamps-
Redding Full Size (to size with max leverage)
Dillon trim Die + 1200 (just to trim in station 3)


Measuring 45 rounds targeting 1.750" I find the following:
1.7508 average length
.0008 stdev in length
.0035 max variation (1.7490" max - 1.7525" min)

So, the trim is generally within a thousandth statistically and a maximum difference of .0035". That seems like that is an acceptable difference given that the resolution I can measure to is 0.0005". All brass is the same headstamp but I tried with some LC and the few I measured were within the max variation as well. I think the trim setup is ok.

Rest of the brass prep (tumble, chamfer, etc) is done. Then I start loading and the problems begin. I checked the rounds before loading and the last prep does not change the above results as one would expect.

Load Setup on the same 650XL with a clamped toolhead
Lee Decapping (flash hole junk)
Dillon powder drop
Redding Competition Seater
Redding Crimp die

I get the following results for my loades (10 random selections)
2.2354" average
0.0259" Stdev
0.0800" max variation

That is unacceptable I think, but when I measure some factory winchester rounds I get this
2.2346" average
0.0297" Stdev
0.1050" max variation

So, the loads are slightly less variable than factory loads but not much. That seems odd to me since I have read about people claiming to load to wqithin 0.001" OAL consistently. So I measured the bullets (Win 55gr FMJs). Here are the results:
0.7415" Avg length
0.0051" stdev
0.0195" max varaiation

Okay, well, the bullets aren't exactly as good in variation as my trim. My understanding was that the Competition seating die would help remove variation but, if anything, the variation in loaded rounds is higher than bullet variation and significantly so. The dies are tight, the seating die is setup per Redding's instructions (compress sleeve, back-off till numbers are on the front, which was 1/8 turn for me). Trim die doesn't influence it (removed it). For kicks I tried flaring the neck with an M-Die but that doesn't change things either. I haven't tried going back to an unclamped toolhead yet but given how well the trim turned out, I'm not inclined to think that is the issue.

Any ideas? The only thing I can think is that the combination of the bullet variation and the seating die are giving me problems but the REdding die is supposed to be the cat's meow. Hmmm...

If you enjoyed reading about "Trouble with my 223 OAL, any ideas?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
Sagetown
December 27, 2008, 05:56 PM
Deavis: You didn't mention the type of bullet your loading. Usually a soft point will be of inconsistent length because of the lead tip. You can actually see some of them are shorter than others. So your OAL will change with each round. Hollowpoints on the other hand prove to be the same length. When seating they tend to be consistent with one another.

Edited: Oops; I overlooked the 55FMJ in your post.
I'm glad I'm not the only one who's had that problem... Never loaded any FMJ's - yet.

Canuck-IL
December 27, 2008, 06:10 PM
I assume the Redding seating die is seating on the ogive...? How consistent is that for the raw bullets you're using? I expect a lot of variation in gross overall length because of the variance in bullet noses, even Sierras. Measurement to the ogive of the bullet should be more consistent.
/Bryan

rcmodel
December 27, 2008, 06:23 PM
Win 55gr FMJ's are very inconsistant in shape, length, weight, and ogive, as are most GI type FMJ bullets.

All the case prep & hair-pulling in the world will not make them shoot better, because they aren't capable of shooting better in the first place.

If you want to go to all that trouble & stress, you need to start out with higher quality bullets.

rcmodel

243winxb
December 27, 2008, 06:30 PM
+1 what RC said

243winxb
December 27, 2008, 06:38 PM
You should worry more about getting the correck headspacing when flrs your brass. go to link and read "Sizer die setting for minimum headspace" http://www.brownells.com/aspx/NS/GunTech/NewsletterArchive.aspx?p=0&t=1&i=1305&mc_ID=2019 RC posted this, its GREAT for new reloaders.

kelbro
December 27, 2008, 07:38 PM
Measure to the ogive, not the tip of the bullet. That's how your Redding Comp seater die works. I would bet that you would then see .001.

If it's once-fired brass, you could also be seeing some case-head variation in the flatness or extractor/ejector blemishes. Once-fired LC brass is frequenlty harvested from fully automatic range sessions. A lot of that brass is not 'true' until you fire it in a bolt-action with a true boltface. That will often square it up. You can confirm this by setting up your measurement tool and rotating the brass. The high spots will become apparent.

SSN Vet
December 27, 2008, 07:50 PM
if their FMJ bulk bullets...
RCModel set you straight

Deavis
December 27, 2008, 08:14 PM
Thanks Kelbro, that is the only comment I needed to see. I'm not loading match ammo, so I'm not concerend with perfect headspace/accuracy as much as I am consistency for function in a set of gas guns. The bullets aren't high quality, but the cartridge OAL variation should match their variation within reason, that was the issue. I took a lot more datapoints and by inserting the M-die into the flow and sizing the neck I got the variation down considerably. The Stdev dropped to 0.0056" which is inline with the bullet variation in OAL. If the ogive is indeed changing as well, then it is probably safe assume that it follows similar variation as the bullet length. Everything is as expected now and I think it lines up with not having the neck resized after the dillon trim die. Even through it doesn't touch the shoulder, it does touch the neck. A quick set of measurements showed the issue quite well and I ran a aset and confirmed the data.

I'll break out my bullet comparator eventually and measure to the ogive on the bullets and see if the variation matches what I find in OAL. I suspect it will.

Sunray
December 27, 2008, 11:52 PM
Make sure your dies are seated properly and locked tight. That causes more variations in OAL than anything else.
Cartridges don't have headspace either.

JDGray
December 28, 2008, 09:08 AM
+2 to RC! Them Win bullets are only good for upclose blasting. Using them on the bench will drive you crazy. At $69 per K, they look inviting, but you get what you pay for, and less:scrutiny:

My Siera 60gr Varmint HPs, all seated within a few thousands of each other, with much more neck tension, and the best part, they produce groups:D

dagger dog
December 28, 2008, 10:47 AM
Are you using the shell holder designed for your press?

The devitation between the shell holder and the cartridge case, and the shell holder and the press ram could cause your probelms.

Is your seating die good and clean at the area where it contacts the ogive of the bullet?

I too have went to .0000th's HELL :evil: the minute I brought home my new digital caliper.

The way I whipped some of my deviation problem, I went back to my dial caliper:D

30Cal
December 28, 2008, 06:48 PM
You're using too many digits.

Fodder bullets will vary quite a bit. Match bullets a little less so. The condition of the tips makes virtually no difference in where the bullet goes.

Take 10rds and maul the tips of half with a pair of pliers and shoot them into the same target. You'll see what I mean.

rcmodel
December 28, 2008, 06:56 PM
+1 to too many digits! :eek:

Had to stop & ponder the question for awhile when I read the first post to figure out the meaning of it all.

Never saw that small a measurement except on my machinists micrometer, and I don't use it for reloading.

At least you didn't use metric measurements like some folks do! :D

rcmodel

243winxb
December 28, 2008, 07:51 PM
Seating Depth Variation << FROM REDDING TECH LINE

There are many factors that can cause bullet seating depth to vary when using our Competition Seating Die. First, make sure you're comparing bullet seating depths correctly. You cannot check bullet seating uniformity by measuring cartridge overall length off the bullet point. You must use a bullet comparator, like our Instant Indicator, to compare bullet seating depths. A comparator contacts the bullet at the bore diameter contact point. This is important, as bullets can vary slightly in overall length.

We have designed the seat stem in our Competition Seating Die to contact the bullet ogive as far down as possible. Our Competition Seating Die features a bullet guide that is only .0005-.001" larger than bullet diameter. This tight fit between the bullet guide and bullet ensures that the bullet is seated straight in the case neck. It also limits how far down the ogive the seat stem can contact the bullet. If the ogive of your bullets aren't uniform, you may notice a slight difference in seating depth. Generally, this isn't a problem as modern bullets are very uniform. In rare instances, when using inexpensive bulk bullets, you may find that the bullets were made on several different machines and then blended.

If your loading press is worn, the ram may not stop in exactly the same spot each time you raise it. Obviously, this will cause variations in bullet seating depth. Although our instructions warn against it, raise the shellholder and adjust the outer, threaded die body to make light contact with the shellholder. (Make sure you keep the contact light, so you don't damage the die.) This creates a "dead length" seating chamber that is unaffected by where the shellholder stops. The only disadvantage to using the die adjusted this way, is that it may be awkward to read the micrometer if it ends up on the back side of the die.

Inadequate or excessive neck tension can also cause bullet seating depth variations. If you're using a bushing style sizing die, make sure you've selected the correct diameter bushing to size the case necks. Our current recommendation, is to select a bushing tha t is .001" smaller than the neck diameter of your loaded cartridges. (See the bushingselection newsletter in the "Tech Line" section of our website for more information.) As cases are fired over and over, their necks become progressively harder. This can cause the necks to "spring-back" excessively when they are sized, which reduces the neck tension on the bullet. Either anneal the case necks after several firings, or discard the cases and start with new, soft ones.

Heavily compressed loads can create problems when seating bullets. Our Competition Seating Die is not a powder compression die. The excessive force required to seat a bullet on a compressed load can damage the die and may cause seating depth variations. Switching to a faster burning or ball powder may eliminate the need to excessively compress the powder charge.

If you have any further questions, please feel free to call our technical support line at 607-
753-3331.

243winxb
December 28, 2008, 07:54 PM
in rare instances, when using inexpensive bulk bullets, you may find that the bullets were made on several different machines and then blended.
<<<from redding tech line

Walkalong
December 28, 2008, 07:59 PM
Rare? Nope, common place.

Cheap is as cheap does, and there is no free lunch. You can find some deals with such bullets as Midways Dogtown bullets etc, but by and large you get what you pay for. There is no shortcut for making match quality bullets.

243winxb
December 28, 2008, 08:06 PM
The 2nd's were also sold in bulk and not marked as 2nd's (meaning not up to standards) I know winchester did this years ago when the 55gr fmjbt was GI . The standard was that the bullets had to group into 3" @ 100yds. Good link to GI ammo types http://www.inetres.com/gp/military/infantry/rifle/556mm_ammo.html

carbine85
December 28, 2008, 08:22 PM
Man, I thought I was picky. This doesn't sound like a problem to me. Looks like you ahve some pretty tight tolerences if you're asking me.

243winxb
December 28, 2008, 08:31 PM
"U.S. military specifications for M193 Ball ammunition require a 55
grain bullet (q 2 grains) at a muzzle velocity of 3,250 q 40 fps from a 20
inch test barrel measured 15 feet from the muzzle. The accuracy requirement
from a test fixture calls for a maximum of a two inch mean radius at 200
yards from ten 10 shot groups (which equates to approximately three MOA).
"Statistically average" M193 ranges from 1.2 to 1.6 inches mean radius,
which is equivalent to 1.8 to 2.4 MOA. Velocity from an M16 rifle or
pressure test barrel usually runs about 3,200 fps due to gas loss through
the port. Accuracy is typically around 2 to 2+ MOA from an M16A1 rifle at
ranges of 100 to 300 yards. M193 ammunition is suitable for use in 1 twist
in 12 inches or faster twists. While commercial sporting rifles in this
caliber usually have one in 14 rifling, the M193 boat tailed bullet is
barely stabilized with that rate of twist at ambient temperatures, and will
not stabilize at all when the air temperature drops below freezing.
http://www.ak-47.net/ammo/ss109.txt

Deavis
December 28, 2008, 10:34 PM
Man, I thought I was picky.

I wouldn't say picky, just trying to make sure that everything lines up as it should. Better to have a great setup that works across the board than a mediocre one that sometimes gives you the results you expect. Another positive is some good stuff was posted by 243winxb for future reference!

243winxb
December 29, 2008, 12:14 AM
just trying to make sure that everything lines up as it should. Check and double check, can't hurt. With 3 different chambers, many barrel rifling twist rates, and tons of different bullets, always pays to be careful and take lots of measurements.http://www.6mmbr.com/223Rem.html

SSN Vet
December 29, 2008, 11:28 PM
+2 to RC! Them Win bullets are only good for upclose blasting. Using them on the bench will drive you crazy. At $69 per K, they look inviting, but you get what you pay for, and less

On the bright side.... I just bought my first box of Hornady 55 gr. FMJBT bullets and they are FAR superior to the Winnies.

$7/hundred for the Win

$10/hundred for the Hornady

If you enjoyed reading about "Trouble with my 223 OAL, any ideas?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!