Bullet seating depth????

I've only recently begun to do measuring on my bolt guns for OAL.  I have the Stoney Point OAL gauge tool with cases for 223, 22-250 and 308. 

From what I've read in the past in shooting books and magazines, and been told by shooters better than myself, is that the bullet is best seated to be .010" off the lands.  Of course some rifles may vary to a degree.

What I've done so far is to take the bullet I want to use in said rifle, check the OAL to rifling about 5 or 6 times, and then seat the bullet .010"s deeper into the case. 

Most of these measured rounds have to be fed one at a time into the chamber, as the OAL is to long to function in a magazine.  For those, I've been using the Score High Benchrest Follower that fits easily into the magazine well.    On a hunting rifle, or one that uses a removable magazine, I just load to the max OAL that will fit and function. 

The two rifles I've done this on so far are Rem's in 223 and 308.  On the 223 I can get 55gr vmax or bt bullets to that OAL.  On the 308 the throat is so long I'll have to go to 180gr to get there.  Soon I hope to try measuring my Ruger 22-250 and see what it can do. 

It does seem that puting the bullets so close to the rifling has made better groups with the 223 but I need to get out and do more testing.

I've tried measuring by puting a bullet into a fired/partly neck sized case to see what readings I would get, but always managed to bungle it.  That's why I bought the Stoney measuring tool.  I'm sure it's not perfect, but it seems to be working so far. 

 

 

 

 

Gunrunner,

You have GOT to be kidding that you can't use the magazine. Well, maybe not.

I think it is a crock of fleas that SAAMI standards mean that factory ammo compliant with OAL limits is nowhere near the rifling. But I guess that's what happens when:

1. Lots of people are clueless about guns;

2. The clueless buy whatever crappy, cheap ammo they can find which is

3. possibly out of standard which can mean

4. the ammo might blow up the gun if it touches rifling therefore leading to

5. Some ambulance chaser hairbag filing a big fancy lawsuit.

End of story, but it shows how a few bad, and dumb, apples make it hard for the rest of us.

I haven't shelled out the change for a gauge, YET.  However, I use the Nosler recommendation that Gunrunner spoke of - use a fired case, seat the bullet in it, chamber it carefully and use that for a reading.  However,  ALL my rifles are for hunting so I won't exceed anything that won't fit into the magazine.  I missed a pretty nice whitetail last year because my 7 STW rounds wouldn't chamber right at the COAL I was shooting them at.  They barely fit into the magazine and when I tried to shuck a round into the chamber it got all discombobulated   Since then, I make sure there's some playing room in the magazine (never exceeding SAAMI specs).  If you're shooting single shot then it's probably no big deal but who can guarantee they'll make it on the first shot 100% of the time.  I've made over 50 one shot kills on big game and I still wouldn't hedge my $$$ on just one shot!  First shot is most important but it's nice to have a second in reserve!

Frustrating as it may be, the gun mfr's aren't going to make rifles whose magazines and barrels put only 0.010" distance between the bullet and the rifling.

 

Dave,  you got me to thinking and I tried the rounds I have on hand into the magazine well of my Remington. These are the vmax bullets and I've only recently been using them. They fit, but just barely.  Seems at one point I had some 69rg Noslers that when loaded out to the lands wouldn't fit in the mag.  On my Abolt nothing fits unless SAAMI spec'd. 

For the most part I like using the bench follower on my target guns.  But for a hunting rifle I do like Mountaineer said, and make sure the rounds function in the magazine with no problems.

So much good advice,  so little time to try it all out. 

     I load 1 cartridge very long . Try to close the bolt and then , go in deepper till it closes tightly. Then I go a half turn deeper. I the case of My 7X57 Mauser, the chamber throat is so deep I don't use some bullets. For Example I tried a 140 grain sieara flat base but after using the method above, I was seated way to shallow, only in the case about a quarter of the .284 caliber, so I chose not to use that bullet.( It might shoot great miles from the lands they often do) I am going to try the 140 grain t shock barnes. I can load this bullet so far out and the rifle is strong enough to take advantage of the increaed powder space. I think using H-414 I can get close to 2900. (got 2850 with a 150 grain B-tip) I conclude that seatring depth is a factor in acuracy and a factor in preasue , but individual rifles and loads often defy the norm.   My most acurate rifle is my 7mmstw and its magazine length causes me to load way off the lands.   ...tj3006

I loaded and sighted in three rifles at the gun club yesterday.  Then we when to my brothers deck and fried Chesapeake Rock fish and drank beer.

At the range talked to some other guys and the conversation moved to bullet seating depth.

Were do you guys seat?  say  we measure off the lands?  or OAL?

\

BEAR

I'm strictly a cast bullet shooter, so I want land engagement for my rifles. Just enough, that I can still eject a cartridge,without the bullet pulling out. With cast, this is your best for accuracy. Back when I still shot jacketed bullets, i would genrally have the best luck seated about.030 off the lands, assuming a short throated rifle.

 I let the rifle decide, some like close and some like far.

What I do when developing a load is this -- I first measure the distance to the lede (origin of the rifling) by a simple method.  I stick the point of a bullet in the muzzle and mark it.  Then I load a bullet backward in an empty case as far out as I can and chamber it (I like to use a just-fired case, and wrap the bullet with toilet paper to hold it in place.)  When the round is chambered the bullet will be pushed back when it hits the lede.

I measure the OAL and add the length of the bullet nose to determine the OAL that will have the bullet touching the lede.  Then I back off a bit.

If I'm just starting with this rifle, I load ten rounds, one with the recommended starting load, one with the recommended max, and the rest evenly spaced (mark them so you remember) and shoot a CAREFUL 10-shot group.  I usually find that three or four fired in sequence fall into a nice group, with the rest out.

The idea behind this is that bullets launched at the vibration node will group well, those launched on the up or down slope of the curve will fall outside the group.  The mid-point of the charges in the close group is picked as the best load.

Then I load ten more rounds (using the chosen charge) with one round almost touching the lands, and backing off slowly in equal increments with the rest and repeat.  I select the mid-point OAL of the group and that's it.

Edited by Vern Humphrey

For about 20 years I had a bottle of black inch that an old time reloader gave me.  I'd load 6 shells and dip the bullet point into the ink and let air dry.  then try a round and see the rifling contact points.  Set the next bullet a little shorter and continue till I just got no contact at all.  The  I'd set the die and run all the longer test rounds thu the seater to my set OAL.

Over the years the label fell of that ink bottle.  Wish I could find some of that stuff.  Todays ink doesn't seem to dry quick and even.

So last year I bought a Sinclair bullet seating gage.  Simple to use and seems more accurate than the old test method (my eyes seem to have a tougher time seeing the rifling marks

BEAr