6PPC Bullet Seating Depth.

[Nick Caprinolo]

I have been told that my rifle wants a seating depth that is set to seat in the lands and allow the closing of the bolt to determine the final depth.

So how far over the ogive do I seat my seating die? I hope I have made my question clear enough.

 

[BoydAllen]

If you are working at home, remove the firing pin assembly if you are working with a live round, or if you are at the range and the line is hot take the rifle to the line, put it on the rest so that it is pointing at the back stop and then do the following. (or you can work with a dummy round) Using the same bushing/neck tension that you will use for the loads that you shoot, seat a bullet long enough so that it will be pushed back when the round is chambered. Yes, this involves some guessing. If you get it too long the bolt lugs will not engage the closing cams and you will have to reset your seating die to push the bullet in the case and try it again. In any case, every time you are about to chamber a round for this purpose, measure its OAL, so that you will be able to determine if the bullet was seated deeper as you closed the bolt, by measuring again, after unchambering the round. If you guess wrong, and the round is short, so that the bullet is not pushed back, you will need to pull the bullet, resize the neck, and try a longer seating. Sometimes I have been able to move the bullet foward a bit with a light whack with an inertal bullet puller. In any case, once you have a round that has had the bullet pushed back, use an appropriate tool to measure its ogive to head length and set your die to produce rounds that are a few thousandths longer.

 

[Nick Caprinolo]

If you are working at home, remove the firing pin assembly if you are working with a live round, or if you are at the range and the line is hot take the rifle to the line, put it on the rest so that it is pointing at the back stop and then do the following. (or you can work with a dummy round) Using the same bushing/neck tension that you will use for the loads that you shoot, seat a bullet long enough so that it will be pushed back when the round is chambered. Yes, this involves some guessing. If you get it too long the bolt lugs will not engage the closing cams and you will have to reset your seating die to push the bullet in the case and try it again. In any case, every time you are about to chamber a round for this purpose, measure its OAL, so that you will be able to determine if the bullet was seated deeper as you closed the bolt, by measuring again, after unchambering the round. If you guess wrong, and the round is short, so that the bullet is not pushed back, you will need to pull the bullet, resize the neck, and try a longer seating. Sometimes I have been able to move the bullet foward a bit with a light whack with an inertal bullet puller. In any case, once you have a round that has had the bullet pushed back, use an appropriate tool to measure its ogive to head length and set your die to produce rounds that are a few thousandths longer.

Boyd

You always come through with the right information. Oh how I wish i lived around the corner from you. Thanks

Nick

 

[gpoldblue]

Boyd

You always come through with the right information. Oh how I wish i lived around the corner from you. Thanks

Nick

I would suggest getting a jeweler's loupe,preferably about 10X or some kind of magnifier,to look for "skid" marks on the ogive. A good place to start is when marks are approximately square...as long as it is wide. If marks are longer than wide,seat bullet a few thousands deeper into the case and look again...adjust for "square" marks. I start at "just" and go into the rifling. Can be done either way satisfactorily.
Be safe. Dan

 

[Nick Caprinolo]

Well problem is solved. First I tried a modified case. Turns out the neck on the case is of course too small to drop a bullet in. Using new bullets in each test, I now have it seated so that I get a small amount if indentation showing the lands. Bolt has a small amount of pressure in closing. Will be at the range Tuesday and see what happens.

 

[dgeesaman]

Well problem is solved. First I tried a modified case. Turns out the neck on the case is of course too small to drop a bullet in. Using new bullets in each test, I now have it seated so that I get a small amount if indentation showing the lands. Bolt has a small amount of pressure in closing. Will be at the range Tuesday and see what happens.

Write down the CBTO that you got on the bullet box and repeat the exercise when you change bullets and also over time as the lands erode.

My rifles are not target chambers but they are 6PPC. Ive tested from light jam to lots of jump and get my best results so far with .06 of jump. So ignore what “they say” and test for yourself.

David

 

[Kergeo]

Write down the CBTO that you got on the bullet box and repeat the exercise when you change bullets and also over time as the lands erode.

My rifles are not target chambers but they are 6PPC. Ive tested from light jam to lots of jump and get my best results so far with .06 of jump. So ignore what “they say” and test for yourself.

David

If you have a good 6 PPC barrel it is best to test the seating depth by loading a tested amount of powder e.g mine likes 27.6 grains of H322 AR2219 in Aus (you must know this before testing for seating depth e.g do a ladder test to find your best load). Load 3 cases each at OAL measurement e.g. my OAL is 2.5775 measured on a comparator nut for my 24" Krieger .070 chambered barrel then go into the land (not out to get jump - read Tony Boyer's book of Rifle Accuracy if someone has a copy & you understand why) in .003 increments e.g. for my rifle 3 at 2.5775 3 at 2.5805 & so on up to 2.5895. Go out & shoot each batch at 100 yards always aiming at the same point (very important) using a target with batch depths noted. Once you have finished study the target to see your best group. That's it here's a copy of my recent results which indicates 2.5895 is the go for me. I am going to fine tune this by doing another 4 lots of 3 shot batches going from 2.5865 to 2.5925 in .002 increments to get even closer if I can.

Hope this helps, Cheers from George in Aus

 

[Michael Huebner]

If you have a good 6 PPC barrel it is best to test the seating depth by loading a tested amount of powder e.g mine likes 27.6 grains of H322 AR2219 in Aus (you must know this before testing for seating depth e.g do a ladder test to find your best load). Load 3 cases each at OAL measurement e.g. my OAL is 2.5775 measured on a comparator nut for my 24" Krieger .070 chambered barrel then go into the land (not out to get jump - read Tony Boyer's book of Rifle Accuracy if someone has a copy & you understand why) in .003 increments e.g. for my rifle 3 at 2.5775 3 at 2.5805 & so on up to 2.5895. Go out & shoot each batch at 100 yards always aiming at the same point (very important) using a target with batch depths noted. Once you have finished study the target to see your best group. That's it here's a copy of my recent results which indicates 2.5895 is the go for me. I am going to fine tune this by doing another 4 lots of 3 shot batches going from 2.5865 to 2.5925 in .002 increments to get even closer if I can.

Hope this helps, Cheers from George in Aus

George,

It really depends on what projectiles you are using, but I would keep going in further. Or alternatively push in from jam and see where it wants to shoot. Also 27.6 AR2219 is a light load.
I would think barely 3250fps here. I think you will find that in the high 28.x to low 29.x is where u need to be with that powder. Give it a try

Just my $0.02 worth
Michael

 

[Kergeo]

George,

It really depends on what projectiles you are using, but I would keep going in further. Or alternatively push in from jam and see where it wants to shoot. Also 27.6 AR2219 is a light load.
I would think barely 3250fps here. I think you will find that in the high 28.x to low 29.x is where u need to be with that powder. Give it a try

Just my $0.02 worth
Michael

Michael thanks mate.The reason I used 27.6 is the recommended max load is 28. I looked at this "Gentner 65gr BT H322 26gr 3100 28gr 3300 7.5 ogive for .050" freebore" which I thought was as close as I could get to Berger 65 Grain BT Target. This was listed on this website under "6PPC Cartridge Guide". I went up to 8.1 & thought the primers were starting to flatten (maybe my eyes are bit too old). I will give a higher load a try but have been a bit reluctant to do so as I thought I might get too much pressure. Thanks again, I am on a learning curve & happy to soak up as much info from experienced folks like you that I can

 

[Ccrider]

Go slow but I can tell you that I was like you about exceeding max book pressure. The guys that shoot these guns with custom chambers know their stuff. It would probably be helpful if you gave them more info on your rifle.

 

[Kergeo]

Yep I will go slow & try 2 grains at a time up to 28.5 & keep my fingers crossed (chicken). If anyone has advice I am only too happy to listen, my rifle specs are: Stolle Panda RH microport PPC, Flavio comp trigger, Kelbly SPG stock with weight system & Krieger LV 6PPC barrel 270. Got a March 48x52 highmaster scope.

 

[jimmymac]

Yep I will go slow & try 2 grains at a time up to 28.5 & keep my fingers crossed (chicken). If anyone has advice I am only too happy to listen, my rifle specs are: Stolle Panda RH microport PPC, Flavio comp trigger, Kelbly SPG stock with weight system & Krieger LV 6PPC barrel 270. Got a March 48x52 highmaster scope.

First off. I am not telling you what load to use. I will say that BR competitors with the type of equipment you are shooting use higher charges than the 27.6 as the 28.5 you are trying to get to. IMO, you'll have no issues with H322 at 28.5 grains but you need to work up to it test it yourself. If no issues, I wouldn't be afraid to go even further.

I know it seems weird to basically throw away the book when you've been depending on load data your whole life.

 

[Michael Huebner]

Yep I will go slow & try 2 grains at a time up to 28.5 & keep my fingers crossed (chicken). If anyone has advice I am only too happy to listen, my rifle specs are: Stolle Panda RH microport PPC, Flavio comp trigger, Kelbly SPG stock with weight system & Krieger LV 6PPC barrel 270. Got a March 48x52 highmaster scope.

Nice gear - Give BM2 ago as well. Which bullets u using?

 

[WayneShaw]

I would suggest searching here for posts made by James Mock and Tim Singleton where they show the method of tuning a PPC, by both powder charge and seating depth. There is no given setting for either one. Your gun/barrel will tell you what it wants.

 

[Tim Singleton]

Develop a system to evaluate powder charge and seating depth
This is how benchrest guys have been doing it for years
3 powder charges light medium hot work those 3 on the same sheet of paper
Work your seating depth in .003 increments shooting a group at each charge. Work from jam out or just off touch back in toward the lands either way will work