Coal too short

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grantman

New member
Hi all, I’m somewhat new to reloading. Just loaded 20 6.5 Creedmoor cases with virgin brass, imr4350 39 grains and 140gr Hornady bullets. My COAL ended up being 2.65”. SAAMI specs indicate min COAL of 2.7”, max 2.82” Planning to shoot in Lmt 6.5 Creedmoor with 20” 1:8 twist. Will it be safe to shoot those rounds or just pull the bullets out and reseat?
 
COAL will vary depending on the bullet ogive [bullet slope/shape], length of the barrel throat [distance between where the chamber ends and the lands/groves begin and the angle with which the lands are cut.

Step 1 - make certain your cases are of proper length
Step 2 - seat the bullet just far enough that the bullet does not hit the lands of the barrel

Your cartridge will be at optimum length for that particular firearm
 
QuickLOAD thinks you'll be OK, but that's a computer simulation and the result varies with which 140 grain Hornady bullet you have (longer makes higher pressure), and knowing your bullet length would help. Short rounds may not feed reliably. You'd have to try that out to see.

Out of an abundance of precaution, I suggest you make up a couple more of those short rounds, one with Hodgdon's recommended starting charge of 37 grains and another with 38 grains. Shoot them in that order, watching for pressure signs. If none appears, try one of the 39 grain loads. If you still don't have pressure signs, shoot the 39 grain loads.
 
Take a cleaning rod with a flat end, plastic slot with the slot cut off. Put that in the cleaning rod and run it down the barrel to the bolt face. Mark the cleaning rod at the muzzle. Lately I've been using masking tape to do that. Now remove the bolt and drop a bullet into the chamber and hold it to the lands with a pencil. with the other hand run the cleaning rod in again to the tip of the bullet and mark the rod at the muzzle again. The distance between the edge's of the tape to the muzzle is the distance from the bolt face to the lands, almost! Seat a bullet to that depth and it likely won't chamber and you'll have land marks on the bullet. Keep the land mark' cleaned off every try until they are no more, with 0000 steel wool. Every time you either can't close the bolt easily, don't force it, set the seating die maybe a 1/4 turn deeper and keep doing it till the land marks are gone and the round seat's easily. You'll be just off the lands then. You might want to keep that round to re-set the die next time. I don't fool with different bullet's in my rifles so I set the die there and lock the lock ring so the die can't be moved in the lock ring. You'll find that that setting will work for any bullet you use though. Change bullet's and that point will not change. Even though you might use different length bullet's the ogive will not move around.
 
Grantman - easy

1 - dummy cart - no primer or powder
2 - seat bullet just far enough it stays in case [no crimp]
3 - put round in chamber [action will not close]
4 - return round to press, lowering bullet seating die 1/2 turn
5 - repeat until action closes

At that point, your overall maximum cart length is reached with that bullet. Back off the bullet seat die 1/4 turn. Bingo
 
which 140 gr Horandy bullet ? COL can be anywhere between 2.680 and 2.80 depending on whether you are talking 140 A-Max or 140 SST,. Also according to the Hornady X manual you are still a full 3 gr under max charge of IMR 4350 for any of their 140 gr bullets. The Hogdon manual is a bit more conservative and lists a max charge of IMR4350 at 41.0
 
Are you setting the COL to the bullet makers recommendations?

You should use the bullet makers COL or an actual measurement for your rifle.

Also are you trying to crimp at the same time you are seating the bullet?
 
Bullet length should make little difference to the overall cart length. Longer bullets simply seat more deeply in the cartridge, they do not extend out from the brass more. The thing that determines how far you can/cannot seat the bullet is the ogive [shape/slope] of the bullet. Spire points will have a much longer COAL than HP or FP.
 
Dumb ? - what’s the best way to measure to the lands
Click to expand...

I do not know about the best, I have a technique that requires a few shop skills. My techniques prevents me from starting over 'a-new' everyday. When I finish I have a transfer I use to transfer the dimensions of the chamber to the seating die.

F. Guffey
 
what’s the best way to measure to the lands
Click to expand...

Buy a Hornady OAL gauge and the proper cartridge.

Failing that, place a bullet in a slightly loose-neck, unprimed case. Push said assembly into the chamber and then use a small probe/stick/wire/ to go into the primer hole (or drilled out primer hole) and push the bullet as far forward as it will go to the lands. Hold it all there (including the wire) while you remove the cartridge and measure the OAL. That's essentially what the Hornady gauge does.
 
My COAL ended up being 2.65”.
Click to expand...
This statement gives rise to the question, "Why". Did you not adjust your seating die? Did you seat to the bullet's cannalure? I'd suggest using the bullet manufacturer's recommendation for the particular bullet you're using at least until you find a good load. Tweeking the "bullet to lands" is the last thing on my list for accuracy...
 
You are searching for something to worry about. Fifty thou is peanuts on OAL with a bottleneck case, not like it was a .40 pistol

Sure, you can chase the lands in a search for best accuracy which is what the guys are mostly describing.
 
i adjusted the seating die 1/2 turn past when the bullet touched per the lee manual i had. I saw the COAL as being the maximum overall length but didn't see a published minimum length in the guide, so wanted to make sure I didn't overshoot the first time
 
"...COAL will vary depending on the bullet ogive..." OAL has nothing to do with ogives. SAAMI OAL is measured from the pointy bit to the flat bit. Ogives apply to the off-the-lands distance. You can forget about off-the-lands altogether until you have a load worked up. Then fiddle with it. If you feel like it. It's strictly a load tweaking technique that isn't absolutely necessary.
"...best way to measure to the lands..." There is no way to measure it. There is no set distance off the lands either. It's entirely a 100% trial and error thing as every rifle has preferred distance off-the-lands. However, you load a bullet long and loosely in an unprimed, no powder case. Chamber it gently until the bullet hits the lands with the bolt closed. The bullet should get pushed into the case. Measure the OAL and back off.
SAAMI max is 2.825". However, 5 thou isn't going to make anything unsafe. COAL doesn't "end up" either. Your seating die may have come loose. Or you didn't set the seating die up right.
 
T. O'Heir,

Northof50's reference is not to measuring COL from the ogive, it has to do with different shape ogives changing the COL when you maintain a particular amount of jump. Note that having the same jump for the two bullets below produces very different COLs as a result of the difference in their ogive shapes.

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Most of the bullets I have worked with stick int he lands if you use Uncleinicks method.

Better is to simply use a respired case, seat the bullet it in excessively long and measure it.

Then try to very gently chamber it.

Bolt won't close, bullet may stick, gently tap the bolt handle with a plastic object (screwdriver)

Measure the length to ensure its not pulled out (ergo the sized case is better)

Just move it back .010 until the bolt closes and no stick (you may get the bolt close and still stick a bit)

At that point you are no more than .010 off the lands.

As the bullet form varies, that is likely to ensure you are .005 or so off the lands.

I then move it back to .020 off that last measurement.

I have had cases (pun) of my being so close that bullet variation is enough to put some of them in the lands (ok, I take a press and seater with me to the range and I can easily adjust it)

Any new bullet I am working with the powder load is down at minimum so I don't have the pressure issue to deal with if its getting a bit too close.
 
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