How Do You Get Consistant COAL?

[samnev]

I'm using a Forster Ultra Match seating die. Bullet length on 168 grain SMK varies buy as much as +/- 0.005" so no matter where I set my seating die I rarely get consistant 2.8 COAL. Am I doing something wrong or is it something I have to live with or constantly reseat the bullets? I've talk to Sierra about this and was told the variation is normal due to the manufacturing process, go figure.

 

[deadly0311]

Re: How Do You Get Consistant COAL?

Measure from the O-Give instead Bullet Comparator and measure from a more predictable point on the bullet, the ogive.

 

[Fuzzball]

Re: How Do You Get Consistant COAL?

What deadly means is the rifle couln't care less where the tip of a bullet is, it only cares how far it travels before contacting the rifling. That demands checking off the ogive (OH-jive).

Most guns care a lot less about that than some seem to think. The seating tolerance is commonly as wide as 10 thou or more IF the seating depth is in the right range.

 

[Swift One]

Re: How Do You Get Consistant COAL?

When I get a batch of bullets, I measure each bullet at the ogive with a Hornady bullet comparator. I seperate the bullets accordingly and keep them in gladware containers with the measurement written on the lid. When i'm reloading, I then measure the COAL with the bullet comparator again. This has given me consistent COALs with my ammo. I use SMKs and have found that while they are quite consistent in weight, they do vary considerably in length when measured at the ogive. I have found the exact opposite results with Hornady SSTs.

 

[jrob300]

Re: How Do You Get Consistant COAL?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Craig Travis</div><div class="ubbcode-body">When i'm reloading, I then measure the COAL with the bullet comparator again. This has given me consistent COALs with my ammo.</div></div>

This is the best method, as I learned the hard way just yesterday.

I did check the bullets for base to ogive, weight and base to tip, however, I did not take into account the fact that the seater does not necessarily bear on the ogive and if the bullets vary in shape somewhere between ogive and tip, the COAL will be different. The only way to know for wure is to measure the finished COAL at the ogive of every round.

My problem occurred in a lot-to-lot change of Hornady Amax's, but I've heard that Sierra does not necessarily use one machine/lot# and can get within-lot variation.

John

 

[Swift One]

Re: How Do You Get Consistant COAL?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> My problem occurred in a lot-to-lot change of Hornady Amax's, but I've heard that Sierra does not necessarily use one machine/lot# and can get within-lot variation.
</div></div>

This has been my experience. Like I said though. Just meaure the ogives of the bullets themselves then seperate the bulletts accordingly.

 

[Cigarcop]

Re: How Do You Get Consistant COAL?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Craig Travis</div><div class="ubbcode-body">

This has been my experience. Like I said though. Just meaure the ogives of the bullets themselves then seperate the bulletts accordingly. </div></div>

This is the only true way, time consuming but the only way

 

[ArcticLight]

Re: How Do You Get Consistant COAL?

And then after all that work, you, the shooter, still must be able to shoot as well as that bullet is performing.

I used the Redding comp dies and never had an issue - itwas never noticeable at my skill level.

That's a 3.5" group at 600 yards with a 2.810 +- .005

I would not worry about it. That's just me though.

 

[Cigarcop]

Re: How Do You Get Consistant COAL?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ArcticLight</div><div class="ubbcode-body">And then after all that work, you, the shooter, still must be able to shoot as well as that bullet is performing.

I used the Redding comp dies and never had an issue - itwas never noticeable at my skill level.

That's a 3.5" group at 600 yards with a 2.810 +- .005

I would not worry about it. That's just me though. </div></div>

I'll agree with that too...after all its just a "head game" !!!

 

[marduk185]

Re: How Do You Get Consistant COAL?

measure measure measure and sort.

 

[samnev]

Re: How Do You Get Consistant COAL?

Thanks for the reply guys. I didn't think there was any easy way to get the job done.

 

[RECKON SO]

Re: How Do You Get Consistant COAL?

Redding Competition bullet seater + Consistent press manipulation = about as good as its going to get, for me anyway. I dont sort bullets and brass cause as much as this stuff costs I aint gonna throw any away anyhow. I figure if I am getting quality components to start with and shooting a rifle thats built right my gear is going to be way ahead of me anyway. Granted Im nowhere near the top of the precision riflecraft food chain I still think more time shooting as opposed to stressing out about tiny little details that the perfection there of can be easily blown away with the slightest misjudgement of yardage,wind speed/direction or improper shooting form or any of the other 500 things that you the shooter have to do to capatilize on absolutely perfect ammo. I do pay attention to what I am doing when loading to get the best I can withing reason but I have given up splitting hairs when Im putting bullets together. YMMV

 

[samnev]

Re: How Do You Get Consistant COAL?

It just makes me crazy that paying as much as we do for SMK's they can't make their precision bullets to a precise length.

 

[jrob300]

Re: How Do You Get Consistant COAL?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Santo</div><div class="ubbcode-body">It just makes me crazy that paying as much as we do for SMK's they can't make their precision bullets to a precise length. </div></div>

I don't remember if it was this thread or another (there are about 3 or 4 threads on a couple boards on the same topic and I didn't read back through this one) but one poster stated that when he called Sierra he found that 8 machines feed 1 lot for 168 SMK's. Sounds like somebody needs a new Manufacturing Engineer.

John

 

[308sako]

Re: How Do You Get Consistant COAL?

deleted in protest

 

[marduk185]

Re: How Do You Get Consistant COAL?

when i sort smk's seconds(get them cheap im just down the road from sierra) i sort them by base to ogive, weight and base to meplat. i usually end up with about 5 seperate bags. usually 80 percent can run in two seperated groups and then the others are really screwball into other bags. my take is that theyre running two main machines with then have some hairball ones when they setup at a beginning of a run that explains the 20 percent that are wildcard. just my guess. but i dont throw anything aay. i just keep them until theres enuf the same to make a batch.

 

[WARDOG]

Re: How Do You Get Consistant COAL?

I have been loading SMK's for the .300 RSAUM (180 Hunting & 190 LR) and .308 (168) for years.
Most recently when loading the 190 gr. for an AR-10 (TU) I found a .015 variation on COAL. I am a machinist so I have the proper overkill metrology equipment to measure consistently. I began measuring the bullets and found the variation there since my cases are tediously sorted and prepped. Since the .300 RSAUM must fit in a magazine fed Semi-Auto I try to stick with the standard COAL.
I also discovered that the COAL affected the seating depth of the bullet into the case, which in turn affected pressures / + or - up tp 40 fps which was making a BIG difference at 800+ yards. Once I started measuring from the Ogive my velocity variation dropped to +/- 15 fps using IMR 4350 (60.5 gr @ 2850fps). I assume that a slight variation the the shape and volume of the Boat Tail on an SMK could easily affect some percentage of accuracy ar LR. I did not know there were ogive variations on the SMK's. I shoot SMK's because of the cost. With a recent acquisition of a Surgeon Scalpel 7 mm WSM, I may move to shooting Berger's. Does anybody have any input of Berger's variation in manufacturing?