What to do about COAL inconsistency?

[Wachsmann]

just like CA48 had described is what I'm doing for my ladder test. I went out from .015 off the lans to .100. probably need to also go to .120 but I've been told that .100 and down should find the sweet spot. shooting a 300 rum.

 

[Barrelnut]

Varying softness of the brass necks can also cause this. I always use my brass in lots of 50 and make sure that they all have the same firing count on them. If brass with the same firing counts are used. They will be work hardened the same and the bullet will seat with the same amount of pressure.

 

[MontanaRifleman]

OK, so I looked at the Hornady Lock and Load Kit

Hornady Lock-N-Load Bullet Comparator Complete Set 14 Inserts

and the Davidson Comparator

Davidson Seating Depth Checkers | Sinclair Intl

Looks like the Hornady is cheaper. Which is best and is the Davidson worth the extra $$$?

Thanks for all the help so far.

I have not checked the COAL in the 300 RUM yet with the 230 Hybrids, but last time I had it out it shot very well out to 427 yds and printed a .2 MOA group. A couple other groups at 212 and 326 were in the .5 MOA range and another .2 group at 100. Maybe using the comparator will tighten things up a little.

I also run my brass in lots of 50. If I think they are getting unevenly worked then I anneal them.

 

[sp6x6]

To accurately measure off the ogive get a comparator, hornady makes an inexpensive comparator that will attach to your calipers and it has caliber specific inserts.

Take a loaded round seated to lands measure it with your comparator (for the hornady model I mentioned) then say your jump is .015. Seat the bullet .015 deeper measuring off the ogive with your comp. as you go. When you reach your desired jump measure your COAL with the comparator. Then you have your New COAL measured off the ogive, which will be consistent from bullet to bullet, unlike measuring bullet oal from the meplat. Hope that was clear.

This is what I do and what I thought we where talking about. Mine are close but not always the same. The comparator and bullet seating stem are not the same or universal size. So the small variations in bullet show up. That is why on my best stuff I micro seat slight long of desired and tune the few that seem to run long in, by checking all then adjust micro seat .001 and run the ones that did not come out the same. A friend of mine that shoots 1000 bench seats his bullets by lbs. of pressure and they are seperated that way for matches, amoung the sorting and multitude of other things he does. Which has helped him shoot over 6 world records.

 

[16Bore]

You can chase your tail measuring off the tip. However you are finding the lands, whether split case, rod stops, or a jam; measure that with a comparator to find your start. Then just deduct your jump there. COAL can vary 0.015+ measuring from the tip. Off the ogive, you'll see it within .001. I use the Hornady one that mounts on the calipers. As for the rest of their "system", it sucks.....

 

[CA48]

This is what I do and what I thought we where talking about. Mine are close but not always the same. The comparator and bullet seating stem are not the same or universal size. So the small variations in bullet show up. That is why on my best stuff I micro seat slight long of desired and tune the few that seem to run long in, by checking all then adjust micro seat .001 and run the ones that did not come out the same. A friend of mine that shoots 1000 bench seats his bullets by lbs. of pressure and they are seperated that way for matches, amoung the sorting and multitude of other things he does. Which has helped him shoot over 6 world records.

+1 this is the same method I use for my ELR ammo.

 

[MontanaRifleman]

This is what I do and what I thought we where talking about. Mine are close but not always the same. The comparator and bullet seating stem are not the same or universal size. So the small variations in bullet show up. That is why on my best stuff I micro seat slight long of desired and tune the few that seem to run long in, by checking all then adjust micro seat .001 and run the ones that did not come out the same. A friend of mine that shoots 1000 bench seats his bullets by lbs. of pressure and they are separated that way for matches, among the sorting and multitude of other things he does. Which has helped him shoot over 6 world records.

If you are talking consistent jump to the lands, which is where the ogive engages the lands, it is what we're talking about. Sounds like a time consuming step but required for a consistent jump.

I'm going to go with the Davidson comparator.

Thank you everyone for your replies and help.

 

[Outlaw6.0]

I run the Hornady comparator with a micrometer adjustment bullet seater. With my 6.5WSM, AFTER setting the bullet to the required jump I measure the OAL via ogive & note (I tend to forget chit).

I then dial my seater back 1/4 turn or so & seat in increments until my round is seated exactly to the desired OAL. I've been able to achieve <.002 variance per lot (on a good day). It's time consuming but it the most consistent way i've found so far.

 

[MontanaRifleman]

I run the Hornady comparator with a micrometer adjustment bullet seater. With my 6.5WSM, AFTER setting the bullet to the required jump I measure the OAL via ogive & note (I tend to forget chit).

I then dial my seater back 1/4 turn or so & seat in increments until my round is seated exactly to the desired OAL. I've been able to achieve <.002 variance per lot (on a good day). It's time consuming but it the most consistent way i've found so far.

Thanks for the input Tyler.

Now I have question on which comparator to go with again. Why not just use this Sinclair comparator instead of the Davidson or Hornady?

SINCLAIR HEX STYLE BULLET COMPARATORS | Sinclair Intl

 

[Outlaw6.0]

Thanks for the input Tyler.

Now I have question on which comparator to go with again. Why not just use this Sinclair comparator instead of the Davidson or Hornady?

SINCLAIR HEX STYLE BULLET COMPARATORS | Sinclair Intl

I like the concept however, I see no way to mount that to your caliper. With the others, they are fixed via set screw to your calipers. That seems to me, to be a much more consistent way of measuring.


t

 

[MontanaRifleman]

I like the concept however, I see no way to mount that to your caliper. With the others, they are fixed via set screw to your calipers. That seems to me, to be a much more consistent way of measuring.


t

You are probably right about the fixed comparator being more consistant but I think I'll give it a try anyway. If it doesn't work, I'll get the Davidsons.

 

[Outlaw6.0]

You are probably right about the fixed comparator being more consistant but I think I'll give it a try anyway. If it doesn't work, I'll get the Davidsons.

Hey, nothing wrong with a product review!


t

 

[MontanaRifleman]

Hey, nothing wrong with a product review!


t

I just remembered that my smith made me 2, what he calls, "what's it" gauges from the barrel cutoffs from my 6-284 and 6.5 WSM. They are ~ 1.4" long and .56" in diameter. One end of it was reamed with my reamer to help determine seating depth to the lands and other things. The other end was funneled, to act as an aid in pouring powder. I took the funnel end of the gauge and slipped it over top of a few of my seated 6.5 WSM rounds loaded with 160 Matrix and was easily and accurately able to determine the jump variance in the rounds. 2 of the rounds I measured had a COAL variance of .0135 and a jump variance of just .005, Looks like I got my fix for the 6.5mm and 6mm.

 

[Outlaw6.0]

I just remembered that my smith made me 2, what he calls, "what's it" gauges from the barrel cutoffs from my 6-284 and 6.5 WSM. They are ~ 1.4" long and .56" in diameter. One end of it was reamed with my reamer to help determine seating depth to the lands and other things. The other end was funneled, to act as an aid in pouring powder. I took the funnel end of the gauge and slipped it over top of a few of my seated 6.5 WSM rounds loaded with 160 Matrix and was easily and accurately able to determine the jump variance in the rounds. 2 of the rounds I measured had a COAL variance of .0135 and a jump variance of just .005, Looks like I got my fix for the 6.5mm and 6mm.

Now THAT could be perty dern useful... wish i'da thought of that.


t