Seating depth, how long can I go?

[Grimstod]

Ok so I loaded 21 rounds of ammo up at different seating depths. These are all .005ths apart. As you can see I don't have much more to go but the gun keeps shooting better as I seat it closer the the lands. Should I keep going 5ths at a time or is one of the groups in my target look good enough to set up a node.

3.436 OAL
1.279 MOA

3.441 OAL
1.242 MOA

3.446 OAL
0.844 MOA

3.451 OAL
1.746 MOA

3.456 OAL
1.278 MOA

3.461 OAL
0.823 MOA

3.466 OAL
0.884 MOA

Should I me sure vertical dispersion? These are shot at 150yards.

 

[Patch700]

...out of curiousity , did you do those seating depth groups one at a time or round robin? ( 3@ .446" 3@ .441" etc) .

Reason I ask is that i've found when I do my powder charge testing I do it in a round robin fashion and also now do my seating tests the same way and it seemed to work better for me with respect to getting a true reading on what the averages would be per setting.

 

[Grimstod]

I fowled the barrel first then did my shots in order.

 

[dkhunt14]

When you use a powder charge test you use the same aim point so round robin won't hurt you. When doing this seating test you have different aim points and moving the gun to compensate can hurt accuracy. I wouldn't do them round robin. I have seen some guns shot really good with only 50 or 60 thousandths of bullet in the case. Matt

 

[Grimstod]

Thanks mat I will keep going longer then

 

[Webster]

What caliber is the cartridge? Can you describe the rifle?

 

[Grimstod]

This is a 7.62x54r the receiver was originally a Izxy 1942 really ugly looking. Terrible machine work. It stripped it down to just the receiver. New bolt. New Loather Walther barrel with a straight contour and a lot of Finnish parts. SWFA scope. I went with a 311 bore from LW. The free bore in it seams excessive to me.

By the way I think I failed to mention that the OAL is measured with the Hornady Ogive comparator gauge. So its shorter then that. I am just measuring to the Ogive plus an inch of the Hornady gauge.
Actual length to the tip of the bullet is more like 3.140 witch is much longer then the Lyman reloading book says SAAMI specs it to. My bullets at this length are still not jammed.

 

[tisme]

I'm not an experienced reloader but I asked the same question at a F training session and was told so long as you can't twist the bullet in the case, by hand, its fine.

 

[spclark]

The group @ .466 looks fine to my eye, dispersion's mostly all horizontal. How was the wind during your range session? I typically measure vertical alone, figuring I'd rather pay attention to holding the same point-of-aim during a string & ignoring what the wind's doing.

 

[jsthntn247]

3.464 is your ticket based on that test.

 

[Grimstod]

It was a little gusty. I did not pay attention to wind. I will try some that are a little longer. And the 3.464s too

 

[nastynatesfish]

I'd stop with it at the 3.466. You'll be getting close to the boat tail. Is it a hunting gun or just a range gun? You could also pull the barrel and have the chamber reset to get rid of some of the freebore. Not sure what weight bullet your running but I think that is what is do. Just have it so you've got a bullet diameter in the neck with out the boat tail and have someone throat it for that oal

 

[Grimstod]

Mainly a range gun. I would like to use it hunting but would need a better bullet for controlled expansion.
It is a 174gr a Sierra MK HPBT. If only they made a 190gr for the 311 cal then I could set it out farther. But I think I am def going to get the chamber reset like you said.

Read a little about the gun here
http://bulletin.accurateshooter.com/tag/grimstod/