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Found some very informative videos here; http://www.wheeleraccuracy.com/#!information/p62ad
I'm going to try out the sizing brass then setting distance to lands using these methods. Anyone else using these?
EDIT: I recommend watching the "sizing your brass" video first. This is the first time I've read or heard the reason WHY you bump the shoulder back from an "as fired" chamber fit dimension. Then go to the "measuring to the lands" video.
That is a very good method. Brass may need to be fireformed for this method to work. New unfired brass may not be long enough at shoulder to be tight in chamber.
Thanks, short round. I wasn't clear on my post and edited it to cover your suggestion about brass. There is a great video on that subject.
Much appreciated.
The length we seek is the distance from a closed locked breach face to the point 'A' bullet contact the lands.Quote:
Originally Posted by short round
Alex's method is more or less the same idea as using a split neck case. When using a split neck case the bullet is started in the case long and when chambered and the action is locked to battery the bullet is seated to depth. Using his method the bullet is again seated long but it's depth incrementally seated deeper using a die until the bolt can be locked to battery and the case and extracted without the bullet sticking or barely sticking in the lands. The difference? His maintains a more consistent neck tension on the bullet when seated whereas the split neck case's can vary.
The case used in both methods could be .010" short casehead to shoulder, rim or belt and wouldn't make a difference. As a matter of fact a case short in head clearance is preferable when using either method. Its only purpose is to hold the bullet and take up the empty space between the breach face and the lands.
Bill
Well, I'm totally frustrated now. I spent the better part of yesterday and this morning experimenting with this method of establishing distance to lands with no success whatsoever. I started with the bolt disassembled as per the video, progressing with further disassembly until both baffles were removed, but still could not develop a feel for the bullet un-sticking from the lands. A word of caution here, with no spring tension to hold the bolt retainer pin in place, it may fall partially out of the hole while in battery position, making for some real fun times trying to open the bolt.
I used a chamber brush and a endoscope camera to verify neck and throat were clean of carbon, used FL sized brass and neck only sized, and no brass at all. Bolt always had a slight hitch upon withdrawal.
I could get consistent numbers with my Hornaday OAL gage, so that's what I'm going with.
I guess the video posters action is much different than a Savage SA when it comes to lock up. Anyone else try this method and have a similar experience?
I'd say stick w/the Hornady gage.
I use a similar method as well to find the lands.Quote:
Originally Posted by Texas10
I'm going to ask a stupid question though....On the video where he is bumping the shoulder back, his "Fire formed" brass will not chamber....I have never had a piece of brass not chamber back in the rifle I fired it in! Only on one occasion did this happen and the brass was NOT new fire formed brass and it did need to be annealed and full length sized before it would chamber.
I guess I don't get the reason why his would not chamber???:confused:
I am at a bit of a loss about that too. Unfortunately, this thread is not getting as much attention as perhaps it deserves, probably because everybody is focused on shooting season, so maybe were not going to learn as much as we might otherwise on this particular subject.
In my gun, headspace is minimal and brass growth is nearly nonexistent (I neck size only) so fire formed brass fits perfectly. I recently installed a new barrel so I had to FL size all my brass and run them through a neck trimmer, then fire form them again to the new chamber before commencing fine tuning load development. PITA.
I have tried the bullet seated long in a split neck case method, painting the bullet with a felt tip marker method, and Hornaday OAL gage method and have finally decided that seating a bullet to within a thousandth or two is not within my skill set, and perhaps not necessary or even possible for my particular loading and shooting equipment and style.
this is my take on this...i use to neck size only for a long time but in my case after a few firings my cases would get very tight so thats when i started FL sizing every time but i set my die to where i have just a slight feel when i chamber a round and since ive started FL sizing my ammo is more consistent.
in the video he bumps his shoulders back quite a bit but i bet he is running a tight neck chamber...if your running a no neck turn chamber and bumping your shoulders back as far as he does its like fire forming every time because the case is pushed over to the side because of the ejector pushing on the back of the case and no other real support...with a slight crush fit on the shoulder into the chamber it may or may not line the bullet up with the bore better but IMHO its better than having the case cocked off to one side.
i run tight neck chambers.. .295 neck and turn to .293 and still size to have a slight crush at the bottom of the bolt closing.
the other thing is he is running a high end custom action and is the reason his method works for him...with a factory action its hard to get the feel for what he is doing because the factories are not smooth.
i use the hornaday gauge and push the bullet snugly into the bore..i know im pushing it past touching but i get consistent measurements and a good starting point but i always figure that my measurements are most likely .005 into the lands...trying to get a bullet to just touch the lands with the hornaday gauge and get consistent readings is never going to happen...next time you check put the mod case into your chamber on the tool and wiggle it around and i bet the case is loose...now add your bullet and take a measurement then repeat trying to keep the same pressure but wiggle the case around just a little and i bet your measurement is different every time.
when starting with a new barrel i will start at least .015 off the lands which for me is actually .020 on my calipers because as i said i figure im pushing the bullet into the lands at least .005...when i find a good load i will move the bullet .010 closer and .010 farther off and this tells me if the bullet wants to be close or a big jump.
i dont shoot VLDs because they are a PITA and out of all the barrels ive shot the best seating depths have been from .015 off to .035 off and most have shot best at .025 off the lands.
When I started loading there were no special tools available for finding the lands.
We simply seated a bullet long in an empty unprimed case and adjusted the seating
die until the rifeling marks disappeared or were very faint. Since marking pens didn't
exist either a match was used to smoke the bullet. The final version was then saved
for future die adjustments for that bullet. I still use this method and see no reason to change.
I do use a shortened case and the caliber specific gauge for finding the case length for each gun.
Ive known a few guys who had good guns and went to great length with how they load.
Yet in 20 years they never even won a relay at Williamsport.
Yet others were in the hall of fame in 5 years, got bored and quit.
The main reason there isn't more interest here in this type of conversation at least in my opinion,
is that most aren't interested in being that technical.
For once I actually 100% agree with yobuck! I do less work in my reloading room then 90% of the shooters I shoot against. Some of them are going through every bench rest reloading technique in the book, but I can tell you that 100% of my misses in competition have been shooter related every single time unless a barrel was at the end of it's life span(6mm) and getting unpredictable. I still use a Lee 50th Anniversary kit. Collet neck sizing die. I only use the LNL OAL Gauge to ensure I'm not jammed into the lands. I use a ChargeMaster for powder and load dev I stops when I hit the velocity node I'm looking for and 1/2MOA or better. 9/10 I have at least 3 1/2 MOA groups in a range of half grain increments and I simply pick the middle one and maybe slightly adjust my charge .2 up or down after the brass has been once fired and again after the barrel gets 200-300rds on it as every 6mm barrel I've had has had a velocity jump somewhere in that range of rounds down the tube.
But if I do all that it cant hurt, right?
And if I don't it might, right?
Take a fired case, neck size it until you get a tight fit using your hand. Insert a flat base bullet inverted and leave it long, carefully chamber it. When ejected you have your answer
The easiest method by far, is to check it with the barrel off the action. Drop a sized case into the chamber and measure the protrusion. Then seat a bullet in the same case, long. Drop it in the chamber and measure the protrusion again. What ever the difference is, adjust your seater die accordingly. When the bullet just touches, it will make a slight ring on the bullet when you rotate it in the chamber. Now if you need to get real technical, you need to add the amount of shoulder bump to that length.
Along those lines, I always make myself or have made, a case gauge. The same reamer used to cut the chamber is inserted into a stub of leftover barrel stock just about 3/4 of the way into the shoulder. With this and your calipers you can set distance to lands and shoulder bump perfectly.
Takes about 15 minutes or less to make.