Setting dies for BTO.

In the process of changing bullets for one of my precision rifles. Savage Model 12 FVSS in .223. I am working at setting the seating die to provide a finished cartridge that will allow the ogive on the Berger 55 gn fb target bullet to just kiss the lands. Painstaking measuring and setting up can help produce the best results.

Step 1. Determine the exact BTO, Base to Ogive, for the particular rifle using a Hornady OAL guage and they exact type bullet that is being used. I like the curved gauge so it can be used on both semi auto and bolt rifles. Lock the length of the moveable bullet when it is touching the lands. Remove tool and bullet.

Step 2. Measure the BTO of the cartridge while still in the gauge.

Step 3. Measure the cartridge separately from the gauge and determine the exact BTO needed for this rifle.

Step 4. Set up micrometer seating die to measurements acquired previously. Usually takes a few tries to get it correct, by trial and error method.

Step 5. Load away and enjoy your time knowing you have done your best.

Whatta Hobby!

More photos to go along with previous. Whatta Hobby!

I do the same but with a fired case and bullet. Size the case mouth just enough to hold the bullet. Chamber, extract, measure, done.

Lots of ways to skin the cat. Whatta Hobby!

Yes there are. Have you compared your fired case to your Hornady modified case. I found the base to shoulder dimensions to be as much as .010" different. Might be worth looking into if you are wanting to be precise.

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Originally Posted by Robinhood

Yes there are. Have you compared your fired case to your Hornady modified case. I found the base to shoulder dimensions to be as much as .010" different. Might be worth looking into if you are wanting to be precise.

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Sure have. Hornady provided cases that I use in 6.5, .308 and .223 are right on the money for SAMMI chamber dimensions as are my rifles. Years ago when I first started using this tool I did comparisons with the old way of making a snug bullet fit on a case and chamber it to set the bullet in to reach BTO. Thanks for bringing that up though. Awareness is half the battle for sure. I find a Sheridan cartridge gauge an invaluable asset on the bench.

I made one of those tools myself and use a casing that was previously a round shot & formed to my chamber.

That is how I did/do mine Dave. It works for me.

I would have fire formed a case too, but the case that came from Hornady is a perfect replication of the chambers on the two Savage rifles I am shooting precision with. Both an older model 12 FVSS and the 30 year old model 10 in .223. I keep a Sheridan open sided gauge on the bench for checking all the time. Whatta Hobby!

Fired case bumped to just chamber.
Loose neck, put a little Goo (was using epoxy, someone suggested blue LockTite) in the neck.
Insert bullet long, chamber, muzzle down, let cure, remove.
Label, with round count.
Use to set seating die, directly, without having to transfer measurements.

Speaking of skinning cats.....Load long and let the bolt closure do the seating.
I have my 284-ELF shooting in the high ones and low two's with a .0015 neck
tension number, 4th fired case with good carbon, and a 50/50 mix of graphite
and moly neck lube.....I experimented with this method using cases with only
one or two firings and the results were only good for shooting in the threes.
Bullet release is another key factor, but you still have to do your part.....

NF1E.....Any 100 yard targets to post with your method ??

#4 was bench manners, as it was pretty calm during this particular match's relay.
Must have leaned on the stock, since in the short game, I shoot free recoil. Still got
got the ten though !! In UBR and since I shoot 7mm, I have to shoot on the .308
target.

Attachment 10417

Your rifle must have a pretty new barrel.
In all of my .223s, admittedly shot a lot, bullets 55 grs and under all fall out of the neck before they hit the lands.
My newest .223 has over 5,500 rounds down the barrel but still is improving my 5-round averages at 100 yards.
Last few sessions have averaged 0.249 for 24 groups with 52 gr ELD-Ms with N133 powder but they were seated no where near touching the lands.
They were seated between 2.260 and 2.276 OAL. Best results (0.240) were with them seated around 2.273-2.276 OAL.

For comparison, the best performing bullets are 73 gr ELD-Ms that average 0.245 for all groups shot. The best results were 0.226 for 16 groups sot at 2.365 to 2.368 OAL with N540 and Varget powders.

Since 2018, that rifle has averaged 0.282 for 1109 groups, all the 5-round groups it has shot, even the bullets and powders it didn't particularly like.
Strangely, the 75 gr ELD-M are some of the worst performers averaging 0.374.
Can't figure that our since the 77 SMKs average 0.255 with the same powder and my 1:9 twist isn't even supposed to stabilize 77 gr bullets.

You're right, "Whatta hobby!"

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Load long and let the bolt closure do the seating.

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Eunice Berger did it that way.

I've wondered about that method as well and was thinking of trying it with some 105VLD's that I have. I'd have to change something since my neck tension is too high for that right now. They do ok being jammed about .010".

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Originally Posted by charlie b

I've wondered about that method as well and was thinking of trying it with some 105VLD's that I have. I'd have to change something since my neck tension is too high for that right now. They do ok being jammed about .010".

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Never had any luck with the load long method and VLD bullets. A tangent ogive bullet works
quite well for me. I'll say that since a tanget ogive bullet is more on the blunt side, it's more
of a positive stop. When shooting the longer ranges such as Ridgway, I started experimenting
with the more tangent 180 gr SMK's in my SA284. I could'nt test much more since those bullets
dried up on the market and primers were getting scarce.

I had not thought of that aspect of it. I guess I could leave well enough alone :)

[QUOTE=charlie b;521735 I guess I could leave well enough alone :)[/QUOTE]

Where's your sense of adventure ??......LOL Pick a dead calm day and do at least
a 5 rounder for a cheap look.

ROFLMAO Yeah, what's it going to cost me? 5 rounds?

Hard part around here in spring is a calm day :) I try to get to the range before the 'mountain outflow' starts to do fine tuning (just before sunrise). After that the winds start.

Fuj, you know that leading someone down the rabbit hole is not a good habit to get into :)

in my case, one group doesn't cut it.
Based upon my shooting skills, I can't assume that all 5 rounds will be consistent enough to allow one group to be the basis to conclude anything.
I also don't use a ladder technique either because any one shot could be off and result in a wrong conclusion about what the best load might be.

Statistically, if 4 or 5 5-round groups don't have a standard deviation of 0.050 or less, I don't think there is enough consistency to make a reasonably accurate conclusion.
Usually, I base my conclusions on 20 groups unless a smaller 10+ sample has a very small standard deviation.

Even doing ladders, I have considered 10 rnds a minimum for each test, that is at least 10 rnds of each powder amount and this should be in weighed and segregated cases to amount to anything. Whatta Hobby!

NF1E,
You appear to recognize the same problem even though you are probably a better shooter than I am.

Still we manage to make reasonable decisions with the data we have.
As you say, "Whatta Hobby"

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Originally Posted by CFJunkie

NF1E,
You appear to recognize the same problem even though you are probably a better shooter than I am.

Still we manage to make reasonable decisions with the data we have.
As you say, "Whatta Hobby"

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Don't claim to be a better shooter than anyone else. Since retirement I probably shoot more than most with a range in my yard. I have been running about 10K of .308 a year and like to prepare ammo for each of my rifles so they can do their best. It is an on going procedure that I truly enjoy. Whatta Hobby!