[p] I need clarification on a method I found on this forum for figuring out my rifle's bullet seating depth. The post can be found here: [/p]

[p]https://forums.accuratereloading.com/eve/forums/a/tpc/f/2511043/m/4991020661
[/p]

[p]The question I have is which marking to go off of. You'll see in my picture below a ring around the bullet where the bullet touches the lands. Do I push the bullet into the case to where that line is lined up with the case mouth for MAX COAL and then go .010" deeper? This seems to be very short. Not sure if I seat to that ring or seat .010" below where the case NECK scrapes off the ink and not where the lands scrape off the ink. Thanks is advance for your help. [/p]

Never done it that way. I do it this way.




"This length measurement is based on where the bullet contacts the rifling. I have one of these modified cases for each rifle caliber that I reload. Just take a resized case, and cut 3 or 4 slots in the neck. This is an easy project with a Dremel tool using a cut-off disk. This makes a great chamber length gauge that will grip a bullet with just enough tension to hold it in place. This becomes an OAL gauge for one specific caliber using one particular type of bullet."

I do it like Paul H. You can squeeze the fingers in to get more tension if the bullet moves too easy. Fast and easy, I get better results this way that alot of other methods I have tried over the years.

Very interesting method. I swear every time I sit down to try one method another one pops ups someplace Do you cut the grooves in the neck after you have sized the neck or do you just use a once-fired, non-sized case? I may have to try this...

quote:

Originally posted by DPollard:
Very interesting method. I swear every time I sit down to try one method another one pops ups someplace Do you cut the grooves in the neck after you have sized the neck or do you just use a once-fired, non-sized case? I may have to try this...

Sorry, should have read the post more carefully...I see now where you indicate it is a re-sized case...

If you want to experiment with different bullet profiles to see what works best in your firearm, build a depth gauge from a fire formed cartridge by drilling out the primer hole, thread the hole, and put a long threaded bolt in that rests against the base of the bullet. Deep-seat the bullet that you want to try in the cartridge place it in the chamber and turn in the bolt until it pushes the bullet against the lands, remove the case and the bolt acts as a bullet stop to determine the length you need for the bullet to touch the lands. Since the bolt will not move on extraction, if the bullet is pulled out of the case a bit when you remove the cartridge from the chamber, you can simply push it back in until it stops against the end of the bolt.

Mr mcmillian, I like your idea, and in fact have tried a variation on this method in an attempt to determine seating depth.
I have a quick question if you don't mind. I would like to know where you came up with this idea. Was it an original thought, or did you "borrow" it from someone?
The reason for my curiosity, I came across this idea from a fellow's website claiming to have "invented" the method. Based on some less than polite e-mails from this guy, and some common sense, I wonder.
This same person claims to be a past state champion in, I believe, the 600 yard silhouette shoot.
So I am just curious to see if this idea might have originated in the same place.

I have a large collection of ideas that I have kept and they come from many various sources. The idea here came out of that collection. Unfortunately, to get the most information in the least space I do not record where each idea comes from and I do not recall exactely where I got it. I operate on the principle that if someone posts an idea publicly (with no provision of "ownership") there should be no objection to someone else passing it along (so long as the idea is not taken from information that is offered "for sale", i. e. someones's book).

quote:

Originally posted by R D McMillan:
If you want to experiment with different bullet profiles to see what works best in your firearm, build a depth gauge from a fire formed cartridge by drilling out the primer hole, thread the hole, and put a long threaded bolt in that rests against the base of the bullet. Deep-seat the bullet that you want to try in the cartridge place it in the chamber and turn in the bolt until it pushes the bullet against the lands, remove the case and the bolt acts as a bullet stop to determine the length you need for the bullet to touch the lands. Since the bolt will not move on extraction, if the bullet is pulled out of the case a bit when you remove the cartridge from the chamber, you can simply push it back in until it stops against the end of the bolt.

This is similar to the Hornady Overall Length Guage, correct? I finally broke down and just went out and bought the OAL Guage from Hornady. Had a $10/off coupon sitting on my desk begging to be used Using that tool has proved to be very easy and I have confidence in my results. Since I still consider myself new to reloading I figured I'd wait on using home-made tools until I have more experience reloading. I enjoy use of all of my fingers

After purchasing the Hornady Overall Length Guage and loading up some rounds .010" off the lands, I measured the overall length from the tip of the bullet and am quite a bit longer than the book's max COAL. Is this something to be concerned with? The bullets chamber nicely and the bolt handle closed easily....

Hey D...you just learned one of the "secret knowledge" secrets from days of yore.

The explaination...SAAMI has set specifications so that ALL the different manufactures of reloading component can have a specification to build to such that "most" of the items will fit within a certain tolerance limit...bullet OD, case length and dimensions, "normal" COAL for the "normal" weight bullet "normaly" used like 50-55 gr for a 223, 150 gr for a 308, 180gr for a 30-06...ROUGHLY speaking.

Bullet makers make bullets to a specific OD... NOT to a specific length...and bullets can have a variation of 0.025" plus or minus a bit in some cases...hollow point bullets are especially susceptable to variation in length due to the way they are made...lead bullets get their noses squashed, protected point bullets are usually pretty uniform, but the only way to know is to MEASURE and SEGREGATE.

Your main concern is the base to ogive distance to the lands which the OAL guages give you...it doesn't matter HOW LONG the overall length is as long as it works through your magazine and doesn't matter a whit in a single shot or if you single load a magazine gun...or the concerns of a tubular magazine.

Almost every reloading manual has references to this and some have excellent reference material.

Now is the time to go over to some of the forums like 6mm BR, Saubier, and the varminting/benchrest/longrange forums...most of them are chocked full of all the information you are looking for as far as reloading and all Iit's nuances.

All this stuff is covered like a second skin...just do a bit of searching and lurking...

You ALSO need to understand that the ogives of a box of bullets have variation...measure every bullet in a box and separate them into groups...when you understand what is going on there, you REALLY ARE becoming one of us "nurdly, analized, measure EVERYTHING... TWICE... BUGEYED, bughole obsessed nerds" ...

But that's OK.

Luck

I used my new overall length gauge today to seat my bullets .020" off the lands and am amazed at the results.

The load is as follows:
Remington 700 .270
135gr Sierra Matchking HPBT
56.3gr H4891SC
Seated 0.020" off lands
CCI 200 Primers

The pics below are off a 4 shot group at 100 yds. I am posting 2 pics because I am not sure the "official" method of measuring groups so I measured outside edge to outside edge at the widest point and also center to center at the widest point. Thanks again to all who replied and helped me with this.

RD, How do you keep the case from rotating in the chamber when you turn the bolt, thereby keeping the bolt from seating deeper into the case to put pressure on the bullet to seat it deeper?
Just curious. I haven't used this method but, I am interested in trying it.

I use a case fire formed in that particular firearm and (so far) I have not encountered a problem such as you envisioned.

You have to know the chamber specs to start with..

To do this I use a 3 ft. dowl of proper size, meaning not to big to slide down the barrel.

With bolt closed runt he dowl down the bore from the crown and make a pencil mark on the wood..Now put a bullet (just a bullet not a cartridge)in the lands and very lightly tap in with anothe short wood dowl. Now run the long dowl back down the barre until it touches the point of the bullet you put in the lands. Now make another mark on the wood dowl..

Measure the distance between the two marks and you have your specs..so you can now set your die bullet seater X thousands off the lands based on that measurement..You then have to experiment with that X thousands distance to tweek your load..

Is all this worth it for a huntintg rifle? not IMO, as and many rifles still shoot inch groups at 100 yards. My Brno mod. 21 shoots the 130 gr. 7x57 Speer bullet in one inch groups all day long and its throat is set for a 175 gr. bullet seated out to half way to the cannalure of a Hornady bullet..That 130 has to jump damn near a half inch I suspect.

Most rifle are factory rifles and its all for naught as they have long throats and short magazines, so all you can do unless you singly shot the loads is make your OAl fit the magazine and hope for the best and btw it usually works out well enough for any hunting rifle or even varmint rifles, but not for bench resting..