Another .257 Wby Question: Seating Depth

[HereDuckyDucky]

I just measured the jam point on my .257 wby (factory vanguard) using a sized case, seating a dummy round extra long in the die, and measuring the COAL after seating in the action. My COAL at jam is 3.540. My previous reloading for this rifle was done at 3.250 because that was the previous owner's reload recipe for this rifle, and that COAL is longer than most maximums listed in my manuals. I am now realizing there is ton additional seating depth potential for this chamber.

Question: Is there any downside to seating further out? I typically start my seating .020 off jam, so I am currently WAY off that mark. Anyone loading their .257 wby with COAL in the 3.3s, 3.4s, or even 3.5s? Bullet is 115gr VLD.

RW

 

[Dr. Vette]

Have you measured your magazine length to see if you can even fit an extended bullet seating? That's often the limiting factor unless you don't mind a single-feed rifle.

Generally, on a Weatherby chamber, don't waste your time measuring to the rifling or worrying about jam.
I never have in the many Weatherby rifles I've reloaded, and have yet to have a problem making accurate loads.

 

[HereDuckyDucky]

Have you measured your magazine length to see if you can even fit an extended bullet seating? That's often the limiting factor unless you don't mind a single-feed rifle.

Generally, on a Weatherby chamber, don't waste your time measuring to the rifling or worrying about jam.
I never have in the many Weatherby rifles I've reloaded, and have yet to have a problem making accurate loads.

Yes. The dummy at 3.540 fit comfortably in the magazine (internal box) and cycled fine (both in and out). It feels so weird to me to consider seating so far beyond the manuals, but I can't think of any reason why it would hurt (other than insufficient contact with the case).

Edit: If I insert the bullet one diameter width into the case, I get a seating depth of 3.307 (bullet touches case mouth at 3.564 - .257 = 3.307). Using this as a safety rule, looks like I don't have as much wiggle room as I originally thought. Though, it does make me want to try seating tests at 3.307 and see what happens.

RW

 

[FEENIX]

Have you measured your magazine length to see if you can even fit an extended bullet seating? That's often the limiting factor unless you don't mind a single-feed rifle.

Generally, on a Weatherby chamber, don't waste your time measuring to the rifling or worrying about jam.
I never have in the many Weatherby rifles I've reloaded, and have yet to have a problem making accurate loads.

That depends on what bullet you are using in your rifle set-up. .257 WBY has a .378" freebore but has no problem touching the lands with 145 Black Hole and 163 Chinchaga and mag clearance.

 

[FEENIX]

Yes. The dummy at 3.540 fit comfortably in the magazine (internal box) and cycled fine (both in and out). It feels so weird to me to consider seating so far beyond the manuals, but I can't think of any reason why it would hurt (other than insufficient contact with the case).

Edit: If I insert the bullet one diameter width into the case, I get a seating depth of 3.307 (bullet touches case mouth at 3.564 - .257 = 3.307). Using this as a safety rule, looks like I don't have as much wiggle room as I originally thought. Though, it does make me want to try seating tests at 3.307 and see what happens.

RW

For seating depth, I use CBTO measurement as it relates to the lands. And then find the best CBTO and COAL for mag clearance.

 

[HereDuckyDucky]

For seating depth, I use CBTO measurement as it relates to the lands. And then find the best CBTO and COAL for mag clearance.

I am using 115 VLDs. If I load to mag length, they are barely seated (only about .024).

RW

 

[FEENIX]

I am using 115 VLDs. If I load to mag length, they are barely seated (only about .024).

RW

I am not telling how or where to set your seating depth, I am just saying what measurement I use and how I set mine.

 

[HereDuckyDucky]

I am not telling how or where to set your seating depth, I am just saying what measurement I use and how I set mine.

Totally get it. I've used similar methodology on some custom .284s. I was just explaining why this one is a bit of an anomaly for me given how much room are in the chamber / magazine.

RW

 

[WYO300RUM]

I'm going to measure my COAL to see what it is. I seated so it just fit in mag with 100 gr. Barnes ttsx and Hammer Hunter Tipped I have other different Berger, Hornady and Speer heavier bullets loaded to test but don't remember coal.

 

[Dr. Vette]

That depends on what bullet you are using your rifle set-up. .257 WBY has a .378" but have no problem touching the lands with 145 Black Hole and 163 Chinchaga and mag clearance.

That's not a normal Weatherby 1:10 barrel, though.
My comment on Weatherby chambering "assumed" it was also standard twist.

 

[FEENIX]

That's not a normal Weatherby 1:10 barrel, though.
My comment on Weatherby chambering "assumed" it was also standard twist.

I, too, am referring to standard SAAMI chambering/reamer .378" freebore/throat length per figure below. Mine is a standard SAAMI chambering. The barrel twist rate stabilizes the bullet and does not affect the chambering.

 

[FEENIX]

Totally get it. I've used similar methodology on some custom .284s. I was just explaining why this one is a bit of an anomaly for me given how much room are in the chamber / magazine.

RW

How and what tool are you using to measure the CBTO? I am having difficulty understanding the anomaly because of some of the means of measurement you are using, like below.

If I insert the bullet one diameter width into the case, I get a seating depth of 3.307 (bullet touches case mouth at 3.564 - .257 = 3.307). Using this as a safety rule, looks like I don't have as much wiggle room as I originally thought. Though, it does make me want to try seating tests at 3.307 and see what happens.

RW

I do not have a 115 Berger, but below are some bullets that I have in my reloading file for my .257 WBY.

 

[HereDuckyDucky]

How and what tool are you using to measure the CBTO? I am having difficulty understanding the anomaly because of some of the means of measurement you are using, like below.

I do not have a 115 Berger, but below are some bullets that I have in my reloading file for my .257 WBY.

View attachment 632813

Sorry. I was mixing some metaphors. I was not measuring CBTO. I was just explaining my situation using two different approaches. On the first, loading to mag length gave me a COAL where the bullet was barely seated in the case. On the second, I seated the bullet .257 into the case (one width of the bullet), which is something I've used as a rule for minimum seating depth.

RW

 

[MagnumManiac]

I will tell you this, nearly all Weatherby's like jump, 2 reasons, it lowers pressure and allows you to use heavier doses of powder and, it provides a smooth pressure curve. This I have tested using the Pressure Trace on several Weatherby cartridges.
You CAN seat close to the rifling, but with .024" of bullet in the neck, is it wise…

Cheers.