Sniper Country Duty Roster collective wisdom


On determining the ( best ) AOL for your rifle chamber:


As far as I know, there isn't a comparator avail for 6.5mm, so I've use a crudder(read
more primitive) method. It required sacrificing a few of ea bullet type and a few cases:

Initially, seat the bullet deliberatley too far out. Place in chamber and close and lock bolt.
Remove round. You will see some righteous rifling marks. This process will have seated
bullet farther into case. This a crude starting point.
Then, place this round into seater die. The Redding micrometer comes in real handy about
now. Spin micrometer down to make contact. Then spin down a little more,say, 0.010". At
this point it becomes a guessing game of sorts. Seat another, unmarked bullet in another
case at this setting. Chamber this rd. and check for rifling marks. If marks are still
pronounced ie. much longer than wide, then down another 0.010 or so on the micrometer.
This took me a few tries. Anyway, when the rifling marks are approx. 1/2 as long as they
are wide, I called that touching the lans. From that point, I could set the micrometer 2 or 3
thousandths lower and get no marks upon chambering. Then, whatever setting gave the
"touching lans" effect, I would double or triple check with another of same bullet type.
Then , make up a dummy rd. and record data on that case: mainly bullet type and
micrometer setting that yielded desired rifling marks. The "lans toucher dummy rd." if you
please. Every time I cha! nged the die setting for another bullet type, I would recheck the
"lans" setting to see if it still gave me the " just touching" effect. So far it has worked, it
just took some time.

Jeff A. <d1k2l3@aol.com>
Smyrna, Ga USA - Thursday, October 01, 1998 at 12:27:38 (EDT)


Sarge takes time away from school studies and wants to do some reloading! He is trying to get some rounds that are even more accurate than what he currently reloads and asks:
Ok guys we are about to start a thread that I'm sure we have had before but I can't find. How do you determine the best overall length for your reloaded rounds? Both before you reload and after the round is loaded? How much set back off the lands gives you your best accuracy? I've heard cheap ways of doing this and I've heard expensive ways of doing this. I want to hear what works best - for you!

Sarge goes back to the school books and waits for many good replies!
 

Sarge <garryrn@dfn.com>
Area 51 , NM USA - Monday, November 30, 1998 at 01:42:05 (EST) 


Sarge,
one of the drawbacks of shooting a Mauser 86 SR is that the magazines limit the OAL of the reloaded cartridges.

But, I have found that a good shooting round with a "long" OAL would do fine when loaded one at a timeinto the chamber, but when firerd out of a Magazine including Mausers 98 and Rem 700´s but especially M 14´s would go to a figure eight group spread out from 11 to 5 o`clock due to two seperate groups, one from the right mag lip and one from the left.
When checking a round that was perfectly true before loading afterwards I always found that the long OAL´s were knocked more out of line than the short OAL rounds.

So you may have the true Match round in your little green box, but what you chamber into your weapon is a "tower of Pisa".

"Ende"
Torsten <lasercon@dialup.globe.de>
Germany - Monday, November 30, 1998 at 04:04:32 (EST) 


Sarge,

I'm finding 175's and 178's seated to 2.835" with a neck size bushing of .307" work real good in my 700P-DM. I'm using 44.0 gr of Varget and don't think theres a better powder with the possibility of VihtaVouri N-540/550. Varget is easier to get for me locally for load development. V-V is next on the list...............

The OAL is best checked with a Stoney Point gauge and the slug you plan to project. Mine are certainly off the lands with a OEM barrel and magazine box length is more critical to me at this point.

peteR
peteR <PNGREIFF@AOL>COM>
Big City, By-Gawd USA - Monday, November 30, 1998 at 09:12:17 (EST) 


Sarge,
There are as many ways of checking O.A.L. as there is cleaning a gun and you will get as many answer's. I made my own on the Stoney Point version. All my custom rifles have had a piece of barrel with the exact same cut as the chamber to use as a guage for setting the O.A.L. A good simple method is to take one of your old case's that has a split neck and resize it and start a bullet in it and then chamber it, it will then be pushed into the case giving you the rough O.A.L. A good thing to remember is NOT all gun's like the bullet's seated out some like a little jump. An old gunsmith told me one time that as a rule of thumb .22 cal likes a little jump and .30 cal likes to be touching and anything in between is anybody's guess and I have found this to be true during the year's. With these new guns I don't think it makes much difference because they all have so much free bore the bullet usually wont even touch the rifeling and stay in the case!!!

Pat <mrbullet@hotmail.com>
USA - Monday, November 30, 1998 at 11:13:37 (EST) 


Sarge - A buddy of mine has the Stoney Point OAL gauge and he likes it alot. I have heard that .01 inch off the lands id the way to start (Sierra video with David Tubb) I am about to start loading for my Savage and will let you know what it likes.

Brent "Swede" Ingvardsen
Brent <koldbore@hotmail.com>
Shreveport, Louisiana USA - Monday, November 30, 1998 at 11:15:44 (EST) 


Sarge; My experience on seating is the same as Pat's gunsmith..
The way I check it is to use a fired (in that gun) case and slightly
size only the front part of the case to the point that a bullet will go in but not tightly. (some won't even have to be sized at all but will be tight enough depending on the brass and chamber) The looser the better as long as it doesn't stick in the rifling. I just slowly close the bolt pushing the bullet back into the case. The result should be a maximum length. This is one of those cheap ways but it has ways to wrong but so do the others. Pat your right about the lengths. Most are chambered so long that it won't go in the magazine if taken to the maximum clearance length the factory leaves us with.
Custom Gun Smith's regularly cut off and rechamber the factory barrels and probably gain more accuracy in .30 caliber range by doing this than anything but free floating barrels. Another option is to determine the length for "target loads" and fire them single shot not using the magazine. For Tactical shooting this is out of the loop of course. The powder charge will vary somewhat in some rifles/calibers.

B.Rogers <brogers@elkhart.com>
USA - Monday, November 30, 1998 at 12:01:30 (EST) 


Sarge.

I have the Stoney Point Oal guage. Also, you need the modified case for whichever chamber/cartridge your testing. You will need the comparator and comparator insert.
So, four items: OAL guage, comparator, insert, modified case.

Also, you need a stainless steel dial caliper. The Soney Point above mentioned stuff is made to "fit" on a stardard dial caliper. With the afore mentioned items you are ready to roll.

Instructions with the Stoney are very straight forward. With any given bullet type, take several measurements as there may very well be some deviation in your readings. Ideally, this should not happen, but it does. In that case, I use the measurement that occurs most frequently.
Anyway, you arrive at a measurement, and that's your comparator measurement for that particular bullet configuration "touching the lans". The comparator is just a piece that furnishes a relative referencing point. Once you find that "referencing number" for touching the lans, then you can go where you want with seating depths and have repeatability.

I find that touching the lans is a good starting point for determining the seating depth that a given combo of rifle and bullet type "likes" the best.

I have read several approaches to determining the optimum(read most accurate) seating depth for any given bullet type. What I do is begin with rds. that are seated to "just touch lans" and then vary the seating depth in increments of 0.005 (or perhaps, 0.010) inches off the lans. You can vary in increments of more or less as time permits.

I will load 10-20 rds. of a given seat depth keeping all other variables the same (powder, brass, primer etc.) and test fire off of as close to a machine rest(sandbags and rear bag are the classic Smyrna maching rest) as I can manage. Everything being equal with only variations in seat depth. Once a best depth measurement has been determined for a given bullet, my experience has been that that depth will generally apply even after you start changing other variables. In other words, it seems that a given bullet config. likes a certain depth regardless of changing powders or powder charges. For example, I've found that Berger VLDs do best when seated on or approx 0.005" into the lans. Sierra Matchkings do better when seated 0.010" off of the lans.

Also, this measuring capacity enables a fairly accurate means of tracking, and keeping up with, throat errosion if I am correct in my understanding of throat errosion.That's fort of an oblique observation on my part.

Jeff A.
Jeff A. <d1k2l3@aol.com>
Atlanta, Ga USA - Monday, November 30, 1998 at 17:37:10 (EST) 


Sarge,
I usually measure OAL by taking a full length sized case and splitting the neck with a hacksaw or Dremal. Then I grind off the extracter rim flush with extractor groove. With this I long seat my bullet of choice and chamber it with the bolt. after removing the bolt I just push the round out carefully with a cleaning rod. I have found that this works better than pulling it out with the bolt and gives me much more consistent readings. I usually stat out .010" off the lands and work my way in. I also never do this with a max load that was worked up farther off the lands. My two cents.

endwrench <toddfant@bigsky.net>
MT USA - Tuesday, December 01, 1998 at 02:17:11 (EST) 


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