understanding the lands

[Toby Bradshaw]

not a chance. how about you?

Mine shoot pretty well.

i am sure that with one of Alex's rifles or any other rifle built by a top of the line gunsmith on a custom action his tecnique will work perfectly. i just don't have one of those rifles yet.

tool marks in the leede and a round that is not perfectly concentric causes issues. one of the reasons that dimension changes after the throat is broken in. i am sure those customs have a well polished throat with the majority of those tool marks gone.

Alex's method works fine on the 2 factory rifles that I have, too.

 

[dcali]

It doesn't matter what method you use - you are just getting a baseline from which to test. Removing the ejector, and going through all that effort to get the ultimate in precision is not necessary or helpful - you're just going to change the OAL anyhow once you do your seating depth tests.

 

[Richard Coody]

whatever works for you

hell all i want is.to get close

 

[dmoran]

It doesn't matter what method you use - you are just getting a baseline from which to test. Removing the ejector, and going through all that effort to get the ultimate in precision is not necessary or helpful - you're just going to change the OAL anyhow once you do your seating depth tests.

For me, my touch point is a lot more then just a baseline from which to test, and is very necessary. It's a continues un-going measurement needed to keeping my rifles in tune. Every time I load my match ammo, throat advancement gets factored into my seating, to maintain my seating at precise depths.

The most precise and repeatable method for me is the stripped bolt method (like Alex demonstrates).
Donovan

 

[Toby Bradshaw]

whatever works for you

hell all i want is.to get close

 

[Tim Singleton]

whatever works for you

hell all i want is.to get close

The accuracy level that you are looking for and the level some of us are looking for maybe like apples and oranges
If it's good enough for you I wouldn't worry about doing anything different for sure

 

[Richard Coody]

The accuracy level that you are looking for and the level some of us are looking for maybe like apples and oranges
If it's good enough for you I wouldn't worry about doing anything different for sure

my little savage 6br shoots pretty good. not a benchrest winner but fun for me.

 

[Tim Singleton]

my little savage 6br shoots pretty good. not a benchrest winner but fun for me.

That's a nice group!
i would take those all day at 200

 

[Richard Coody]

That's a nice group!
i would take those all day at 200

is that a 3 shot group?

bet you have more than $1200 in that rifle.

 

[Toby Bradshaw]

is that a 3 shot group?

bet you have more than $1200 in that rifle.

That's a tournament benchrest target. Competitor #108, match #5 target at 200 yards. Five shots in 7 minutes, in whatever conditions present themselves, generally shooting against multi-gun winners and world record holders up and down the line.

The winners aren't determined by the price of their equipment, but by how well they shoot.

Nice screamer, Tim!

 

[Ledd Slinger]

I suggest to go to www.wheeleraccuracy.com/videos and watch "Finding your lands"
When there you may want to watch more of Alex's video's, there very instructive !.!.!
Donovan

+1 for This ^^^

This is the one way to truly find the exact seating depth where the lands first makes contact with the ogive

 

[Tim Singleton]

bet you have more than $1200 in that rifle.

Your right, but not as much as you'd think.
Bought it used on here from Thud.
Bound to be 10-12 years old
I have put a barrel or two on it since I got it tho

 

[Toby Bradshaw]

My first BR rifle was a $1000 used Seeley Masker cruiser. I made 20 6PPC cases from .220 Russian. The fireforming group (with 70gr Nosler BTs!) was easily covered by a dime at 100 yards. Then with my fireformed brass the next 5 shots (with Bruno 68gr 9S) went into 0.029" -- a .308 bullet won't go through the hole.



It shot OK at 300 yards, too. After winning with it for 2 years I sold it to a guy a few benches down for ... $1000.



The price of a BR rifle is very modest compared to the cost of components to campaign one.

The point of this thread (I hope) is that you can't keep a rifle in competitive tune without knowing exactly where the lands are, and that is a moving target.

 

[Richard Coody]

i really would like to have a quality 6ppc and learn how to shoot short range benchrest. getting close to retirement. maybe then i will have the time to try a few matches. which is more fun score or group

 

[Toby Bradshaw]

which is more fun score or group

Figure out whether there are more group shoots or score shoots near where you live, and start there. A 10.5-pound rifle with a weight system and a PPC/BR boltface can do both.

And for group shooting, practice saying, "The first 4 were in a bughole."

 

[fyrewall]

I watched the entire video, 6 minutes plus. My comments are:

Removal of some Rem 700 type ejector and spring would require a small punch and take time - would you really want to repeat this every time you had a new bullet or possibly a different lot of bullets was loaded/seated.

The gradual deeper seating ending with a final adjustment of .0005 was not shown and ogive variations within the same box would be probably be much greater than that. This would entail repeating the entire seating process down to the last .0005 for each bullet seating.

The headspace of each loaded round would need to be the same.

I thought the business of a final measurement of .0005 ( 1/2 of one thou inch) done by feel was sort of witless. I am not impressed by superfluous tiny measurements.

My method is to use a felt tip pen, 10X magnifier and dummy round . Engagement of lands shows up with the felt tip ink and magnifier. Upon deeper seating and magnified inspection, land marks will not be seen. Next I take 4 more dummy rounds having identical case lengths, with bullet seated the same, ink them up and inspect each one. If engagement marks appear, and they usually do, I seat that bullet deeper and go back and run the others again checking each one . This provides a working seating depth baseline - then seating deeper in or backing out, measuring by caliper the distance between brass base and top adjustment knob of seating die.

Taking a sample of 5, or 5% of 100, and making an assumption of some normal distribution having a 95% confidence level, 2.5 % may be expected to fall outside the distribution on each end of the curve. Producing a big lot of ammo of 500 to over 1500 rounds for a season or some important rodent shoot, this same distribution will still be in effect.

Measuring any dimensions to .0002 to .0005 would not be productive for any my shooting applications. I would expect individual bullet dimensional variations including ogive position, bullet diameter, and bullet/chamber concentricity would vary more than that, possibly in the order of 1.5 times the little tiny amount of .0002.

 

[Toby Bradshaw]

Removal of some Rem 700 type ejector and spring would require a small punch and take time - would you really want to repeat this every time you had a new bullet or possibly a different lot of bullets was loaded/seated.

Yes. Takes about 10 seconds.

The gradual deeper seating ending with a final adjustment of .0005 was not shown and ogive variations within the same box would be probably be much greater than that.

You must not shoot custom bullets. I have measured 1000 custom bullets from the same lot and not found even 0.001" base to ogive variation.

The headspace of each loaded round would need to be the same.

Which it is, within less than 0.0005" for properly sized brass.

I thought the business of a final measurement of .0005 ( 1/2 of one thou inch) done by feel was sort of witless. I am not impressed by superfluous tiny measurements.

When the rifles that you make can shoot like this (below) during load development at 1000 yards, perhaps your opinion will carry the same weight as Alex's.

Measuring any dimensions to .0002 to .0005 would not be productive for any my shooting applications.

Do your "applications" include winning benchrest tournaments?

Try holding your neck thickness to +/-0.0005" and let us know how that works out for you.

I would expect individual bullet dimensional variations including ogive position, bullet diameter, and bullet/chamber concentricity would vary more than that, possibly in the order of 1.5 times the little tiny amount of .0002.

Buy a box of BIBs, Barts, Brunos, etc. Measure them, and then find a good recipe for crow.

 

[dmoran]

@fyrewall
For the "stripped bolt method" if you do not want to take out the ejector/plunger each time, size up a case for a dummy cartridge, then drill a hole through the case-head, a little larger then the ejector and in relationship to its location, and index it over the ejector/plunger for the task. Simple, cheap, and reusable.
Donovan

 

[kvd]

...measuring by caliper the distance between brass base and top adjustment knob of seating die.

I do not understand what you are saying here. Would you mind elaborating on this statement?

 

[dcali]

I'm still not seeing the point in knowing the location of the lands with such precision. Are you BR guys not testing your changes and making seating adjustments based purely on the measurements? If you are testing, then why does it matter exactly where the lands are? Seems like being within a couple thous is plenty.