what comes 1st OCW or seating depth ?

[Willoughby]

when finding a load for a new barrel what comes 1st ?
finding charge weight at or near lands then finding best seating depth
or starting at a single low charge weight and trying different seating depths
edit to add-- I'm loading for 2 new hunting rifles in 300wm and 300prc both are 10 twist
it seems to me any load work up should start with powder charge for vertical dispersion then seating depth for horizontal dispersion -not the other way around ---but I'm here to learn so please inform me the correct way

 

[RegionRat]

Just some friendly advice about generic open-ended questions...
This is another "it depends" answer.

One of the major problems on open gun forums, is too many assumptions and generalities are made about the context of the gun/ammo/shooting we are discussing. It leads to swirl since folks have strong opinions based on what they assume, which conflicts with opinions about a completely different context.

For example, a competition pattern gun that has a barrel and reamer that is well known after hundreds of examples with near identical reamers, versus some unknown factory hunting rifle.

A 6 PPC BR rig or a high power F-Class rig with a heavy section is one thing, an undefined hunting rig with a hammer forged carry weight bbl is another.

Are we assuming single feed, or magazine length ammo? A light, medium, or heavy for caliber bullet and what reamer?

The answers can run wild if we don't narrow things down. YMMV

 

[Straightshooter1]

this ^^^^^^ It depends!

If you haven't read it before, Berger has a general recommendation here:

Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

VLD bullets are designed with a secant ogive. This ogive shape allows bullets to be more efficient in flight (retain more velocity = less drop and wind deflection). While this result is desirable for many rifle shooters the secant ogive on the VLD bullets produces another result in many rifle.

bergerbullets.com

 

[Willoughby]

Just some friendly advice about generic open-ended questions...
This is another "it depends" answer.

One of the major problems on open gun forums, is too many assumptions and generalities are made about the context of the gun/ammo/shooting we are discussing. It leads to swirl since folks have strong opinions based on what they assume, which conflicts with opinions about a completely different context.

For example, a competition pattern gun that has a barrel and reamer that is well known after hundreds of examples with near identical reamers, versus some unknown factory hunting rifle.

A 6 PPC BR rig or a high power F-Class rig with a heavy section is one thing, an undefined hunting rig with a hammer forged carry weight bbl is another.

Are we assuming single feed, or magazine length ammo? A light, medium, or heavy for caliber bullet and what reamer?

The answers can run wild if we don't narrow things down. YMMV

my apologies I'm beginning to load for 2 new factory hunting rifles, a 300wm and a 300prc. both 10 twist from Seekins. I've always found charge weight 1st then adjusted seating depth -but was told today I should be doing it reverse order, I just wanted to see how the pros do it

 

[Willoughby]

this ^^^^^^ It depends!

If you haven't read it before, Berger has a general recommendation here:

Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

VLD bullets are designed with a secant ogive. This ogive shape allows bullets to be more efficient in flight (retain more velocity = less drop and wind deflection). While this result is desirable for many rifle shooters the secant ogive on the VLD bullets produces another result in many rifle.

bergerbullets.com

thank you and yes I have read that.

 

[Jeff Porter]

Do one one rifle each way …. Great opportunity to see for yourself if it makes a difference or takes less rounds to get to the final load.

 

[DaveTooley]

Here's how I do it.
Pick a bullet, maybe two or three, Set the seating depth to just short of "my" touch point. Run the powder charge up until I see signs of pressure. Then I shoot two shot groups at 200 yds in good conditions with wind flags while changing the seating depth in .005" increments. I'm looking for what doesn't shoot. I've had instances where as I pushed the bullet further into the case I had to increase the powder charge. If there seems to be a sweet spot I'll shoot 3-5 shot groups to confirm. If after say 10 2 shot groups, that bullet doesn't show me something I'll move on to the next bullet and do it again. If a barrel doesn't like a certain bullet you can't force feed it.

 

[R.Morehouse]

For me, it's powder first ( in the lands ), seating second, then neck tension & primer, if needed. Dave said it best for me....

Regards
Rick

 

[jelenko]

Set the seating depth to just short of "my" touch point.

Including for a hunting rifle? I assume rounds for a hunting rifle have to fit into the mag.

 

[DaveTooley]

Including for a hunting rifle? I assume rounds for a hunting rifle have to fit into the mag.

You're correct. Except for a couple of 308 Win's I don't have to worry about mag length.

 

[LCazador]

Fireform first then uniform cases then do what Dave Tooley says above.

 

[bobinpa]

Following... to learn

 

[jelenko]

Fireform first then uniform cases then do what Dave Tooley says above.

For a hunting rifle where the rounds have to fit into the mag?

 

[J_idaho]

Have you bought brass for your 300wm? If not I strongly recommend buying the new Peterson long brass. I am not a professional shooter but I’ve been shooting and reloading 300wm for years. 300wm is notorious for casehead separation after 7 or 8 firings. The first firings are the most critical because of the saami headspace is measured off the belt not the shoulder. Starting out with a low end charge weight can help. So I believe using your first firing looking for seating depth is the best for that cartridge. I have settled on hornadys 208 eldm close to the lands running .003” neck interference and only setting shoulder back .001-.002” every firing. The Peterson long brass is only .005” on shoulder shorter new out of box. This keeps the web from stretching on those first firings which is the case life killer in 300wm. Learning to manage recoil should be first thing though. lol good luck.

 

[ShtrRdy]

Here's how I do it.
Pick a bullet, maybe two or three, Set the seating depth to just short of "my" touch point. Run the powder charge up until I see signs of pressure. Then I shoot two shot groups at 200 yds in good conditions with wind flags while changing the seating depth in .005" increments. I'm looking for what doesn't shoot. I've had instances where as I pushed the bullet further into the case I had to increase the powder charge. If there seems to be a sweet spot I'll shoot 3-5 shot groups to confirm. If after say 10 2 shot groups, that bullet doesn't show me something I'll move on to the next bullet and do it again. If a barrel doesn't like a certain bullet you can't force feed it.

What powder charge weight do you use while trying different seating depths?

 

[dgeesaman]

Do one one rifle each way …. Great opportunity to see for yourself if it makes a difference or takes less rounds to get to the final load.

And once you’ve done that you can compare two unrelated pieces of anecdotal evidence.

I would also do what you’re suggesting but keeping in mind it will provide minimal insight into what might be the optimal strategy, if an optimum strategy could exist. But at least it will be interesting.

OP: there is non consensus on this. Beware of anyone who claims to have a 100% certain answer about tuning any cartridge or barrel.

 

[Clancy]

I do seating depth first. There’s nothing more important so I start there. I started that about 10 years ago and there’s no going back. It’s amazing how much better it works for me. You get the depth right and powder charge is dang near irrelevant.

You can find a load that shoots either way, but powder first usually results in a one trick pony whereas depth first creates very wide accuracy nodes.

I think that when you hear a real successful BR shooter does powder first, it’s almost certainly because he’s shot the same bullet in the same chamber with the same barrel configuration for so long that he knows he’s probably within .004 of perfect and so combustion comes first.

Despite whatever you decide, test in .002 or .003 increments with hybrids/VLD and .005 with the fat nose tangent stuff .

 

[DaveTooley]

What powder charge weight do you use while trying different seating depths?

Warm

 

[Bc'z]

I do seating depth first. There’s nothing more important so I start there. I started that about 10 years ago and there’s no going back. It’s amazing how much better it works for me. You get the depth right and powder charge is dang near irrelevant.

You can find a load that shoots either way, but powder first usually results in a one trick pony whereas depth first creates very wide accuracy nodes.

I think that when you hear a real successful BR shooter does powder first, it’s almost certainly because he’s shot the same bullet in the same chamber with the same barrel configuration for so long that he knows he’s probably within .004 of perfect and so combustion comes first.

Despite whatever you decide, test in .002 or .003 increments with hybrids/VLD and .005 with the fat nose tangent stuff .

Clancy were such non conformist. Lol
After finding touch start .020 ITL and move bullet deeper in the case using 2 shots to determine optimum seating depth.
It sure makes reading charge weight results easy.

 

[r bose]

I start with the program, quickload. Input all info for your particular rifle and cartridge THEN, look for the optimal barrel timing for the length of barrel on the rifle that's within pressure specs for the cartridge.

This ALWAYS puts me very close to where I need to be. I can tweak powder charge 1 tenth up or down to find the ultimate load (might depend on powder lot # etc.) but this system has saved me so much time and loading components.