Seating Depth Question

[drenner43]

I'm fairly new to reloading compared to the experience on this site. Been doing it about 1.5 years but nothing extreme. Started to load for dads new 300 win mag last night. It's a sender II. By my measurements I can get by with a OAL of 3.75" and it still load through the magazine. I'm loading 210 bergers. However, with that OAL it doesn't seem like the bullet is seated near enough in the case.

My question is. What is a good rule of thumb to go by for a somewhat novice, as to what is a safe seating depth? How much of the bullet needs to be in the case mouth to be seated enough? I know there are going to be some in depth responses but I just have standard reloading supplies and tools. So help me all you can. Thanks!

 

[BrentM]

Most books say you need the same amount bullet in the case neck as the diameter of bullet. So you need .308 of bullet bearing surface in the neck of the case. Rule of Thumb.

Some people will increase neck tension and run less bullet. I tend to run close to the rule of thumb and test for accuracy based on that seating depth and deeper. Usually works out just fine and I find a decent accuracy node. Many rifles shoot factory ammo fine and the seating depth is .150 to .250 from the barres lands.

 

[FearNoWind]

... Many rifles shoot factory ammo fine and the seating depth is .150 to .250 from the barres lands.

drenner43:

Your relatively new to reloading and others who may not fully understand so that measurement may need some clarifications - so, If I may:
.150 to .250 off the lands is ogive to lands, not bullet tip to lands.
I agree that, as a rule of thumb, diameter of the bullet is a good place to start for establishing minimums for bullet seating.

 

[gohring3006]

I don't shoot the .300 wm but I'm pretty sure it has less than .308 of neck... I would seat them with enough bearing surface to contact all available neck in that cartridge...

 

[BrentM]

drenner43:

Your relatively new to reloading and others who may not fully understand so that measurement may need some clarifications - so, If I may:
.150 to .250 off the lands is ogive to lands, not bullet tip to lands.
I agree that, as a rule of thumb, diameter of the bullet is a good place to start for establishing minimums for bullet seating.

Yeah, thanks for clarifying.

 

[BrentM]

I don't shoot the .300 wm but I'm pretty sure it has less than .308 of neck... I would seat them with enough bearing surface to contact all available neck in that cartridge...

Really? That is a smidge over a quarter inch. I think I have some cases at home in 300 WM, I will look. If the neck is that short I agree with gohring.

 

[Dosh]

43, get a bullet comparator and possibly a OAL gauge. If you are new to reloading these tool will help you a lot. They are not expensive and can be added to in multiple calibers. Good luck

 

[kcebcj]

I don't shoot the .300 wm but I'm pretty sure it has less than .308 of neck... I would seat them with enough bearing surface to contact all available neck in that cartridge...

The statement above by gohring3006 is accurate.

The COAL probably should not exceed 3.6 - 3.65 to get full bearing in the 300 WM with the 210gr Berger VLD. The 300 WM has a very short neck and measures about .265 depending on the trim length.

Here is a drawing of the 300 WM to review.

 

[Unofficial Gun Addict (UGA)]

Drenner... If you shoot me over some information on your load, I'll put it into quikload which will give a warning when the bearing surface is insufficient for your bullet.

Here's what I need:

Cartridge overall length, case length, bullet make and weight.

If you want me to go ahead and run a charge for you, send powder, charge weight, and barrel length.

Ill post it back here for you and try to find the maximum recommended case length that should still provide enough neck to bearing surface contact.

Cheers.