Seating depth for accuracy question

[benfranklin]

After all my years of reloading for the best possible accuracy
with a standard rifle chamber and dies,etc...I have wondered
if it is really worth the hassel...

How many of you are using the satandard SAMMI O.A.L
mentioned in your loading manuals? I have wondered about
this for a long time..I THINK that standard is set,so that
the shell will fit the rifles magazine without being too long.

I have found some of my loadings are so long that they have
to be loaded one at a time..And without anyway of getting
an accurate pressure measurement,if you bullet is jamed
into the rifleing yet your getting great accuracy,are you
acctualy doing harm to the rifle chamber?
I mean are you causing the chamber to corode faster than it
normaly would....Give it some thought..So instead of getting 10
thousand rounds your only going to get maybe 5 thousand.
And then it's time to rechamber and do it over again..

So I guess what I am getting at is it more better to just use
the sammi oal and try different bullets instead of building
extra pressure and gain nothing? Just something to think
about next time your blasting away at a target or whatever...John

[GaCop]

For hunting rifles, I go by the max length of my mag box and seat accordingly. For benchrest single shot shooting I seat either to the ogive or jam into the rifling depending what the rifle likes.

To date I've seen no accelerated throat wear jamming versus normal OTL seating.

[82boy]

If you looking for accuracy, throw away any mentioned loaded speck. Finding the proper seating depth is THE most crutial thing you can do. When loading manuals come up with COAl lenth many time consideration to magazine length is in this equasion. The seating depth of the bullet has nothing to do with the life of the chamber, it has more to do with the amount of powder burned.

[darkker]

I have never cared what the book OAL spec is, always just loaded 1/32" off the lands(heavy bullets, light can't get that far out many times).
With my Savages, I have never had an issue where I couldn't get the loaded cartridge to fit in a magazine also.
There IS a way of knowing pressures that you CAN afford. Look-up "Pressure Trace". They will set you back about the same price as a new gun, and you will be able to KNOW EXACTLY what the pressures are.

Provided you aren't loading "standard" max pressures, AND THEN jamming the bullet; then as 82 said, it has nothing to do with throat erosion.

[benfranklin]

Interesting indeed.....I know that sometimes I read too much..I appreciate
your kind replies..John

[brtelec]

For my hunting rifles and my magazine fed precision rifles I use the most accurate seating depth that will fit in the magazine and feed. For my single shot target rifles I start at the lands and work back from there. I find most load data to be a general reference.

[Martyg]

I just finished a OCL test with a 22-250. I used 37 gns of RL-15 on all cartridges.
#1 touching-.975
#2 -.010 .025
#3 -.25 .050
#4 -.50 .940
As you can tell my rifle likes the bullet about 10 thousands off.
My .223 predator for what ever reason wont shoot unless the bullet has
a BIG jump. Every gun has a sweet spot we just have to find it.
Im a firm believer in finding the sweet spot first then adjust the powder.

[daniel brothers]

find the sweet spot and then adjust the powder....

Hummm.... interesting... makes sense...

I've been loading some 58gr vmax in my savage 110 243... but can't tell how close or how far I am from the lands... what is the best way to measure it...?

[Martyg]

Hornady makes a lock n load OAL gauge.I think there around 30 dollars. They work great.

[davemuzz]

DB,

Yeah.....the first thing you want to do is find the "total chamber space" for the bullet you are using. Remember....this "total chamber space" will be different for each bullet type (ie: Hornady, Speer, Sierria) that you are using as the bullet shape will differ from each MFG. and even from different bullets from the same MFG. This "spot" where the bullet hits the lands is called the "Ogive".

An easy way to measure the total chamber space is to take an already shot brass, and make sure a new bullet will "slide" in and out of the brass easily. Now...and this is the "tricky" part...you want to size that piece of brass.....just bump it enough so that when you insert the bullet....the bullet will slide into the brass with some resistance.....but it won't fall out easy....nor will it be really tough to slide in.

And remember....don't prime nor powder the brass. If you have a Universal DeCapper, then de-cap the brass so you know it's empty.

Now...once you have this brass prepped, insert the bullet into the brass just enough so the brass holds it so it won't fall out. Then, carefully slide the bullet\brass into your chamber, and carefully close the bolt. What you should "feel" is the bullet being "jammed" into the brass. Now, when you carefully remove the bullet, what you should have is a brass-bullet that when you measure it....gives you "total chamber space".

You may also want to take a marker and mark the bullet before doing this...in case the bullet jams into the lands. If this happens, the bullet will be scored by the brass so you can re-insert it into the brass and get the correct chamber space.

So....now you take your calipers and just measure the buller\brass from the case bottom to the bullet tip. So....for example let's say that measurement is 2.750. And let's say you want your bullet seated 25 thousands from the lands. So, you would seat your bullets OAL to be 2.725.

See....easy!!! ;D

[daniel brothers]

Thanks Dave for the great detailed information.... I will try that right now.... what other great tips do you have.... LOL

I won't forget Man...

[davemuzz]

what other great tips do you have.... LOL


Well....actually that's the only thing that I do know. I know nothing else with any certainty. That's why I belong to this forum!!! ;D

[daniel brothers]

LOL... is that why you have that look on your face....LOL

[davemuzz]

What look?
http://i12.photobucket.com/albums/a212/davemuzz/WORK-AMMO-b.jpg


Have you met my brother?
http://i12.photobucket.com/albums/a212/davemuzz/UGLYBROTHERS.jpg