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Bullet seating depth for Weatherby rifles

IFeelRecoil

Bullet seating depth for Weatherby rifles
« on: January 12, 2019, 07:53:49 AM »

I have several Weatherby hunting rifles that I’ve started loading for

My understanding is that they have increased free bore so that the bullet gets a “head start “ or jump before entering the lands. It also is supposedly safer because pressures aren’t as high.

How do you adjust bullet seating depth in this circumstance? Does it pay to bother with this design?

Re: Bullet seating depth for Weatherby rifles
« Reply #1 on: January 12, 2019, 08:13:45 AM »

I have several Weatherby hunting rifles that I’ve started loading for

My understanding is that they have increased free bore so that the bullet gets a “head start “ or jump before entering the lands. It also is supposedly safer because pressures aren’t as high.

How do you adjust bullet seating depth in this circumstance? Does it pay to bother with this design?



It is true that Weatherby's have long free bore so you really can't set OAL so that the ogive of the bullet is .020 off the lands. What will happen if you try to find the lands is that you will hit the slightly undersized free bore and that's all the further the bullet will go. What I have come to do is measure a few Weatherby factory ammo lengths and average that and then use a precision seating die with once fired, annealed and neck sized brass that is trimmed to the recommended trim length. I believe that the highest level of precision can be attained if the bullet is seated to factory depths and is concentric within .001 with the fire formed case.


You have to be careful with book recommended OAL's. Most of my books tell you what barrel was used and it's usually not a Weatherby barrel so who knows if that was reamed to Weatherby spec's or SAMMI specs. Often it's the later so I don't trust them. Measure what you know is safe and use that, it works.
« Last Edit: January 12, 2019, 08:15:42 AM by HighDesertHunter »
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Re: Bullet seating depth for Weatherby rifles
« Reply #2 on: January 12, 2019, 11:55:24 AM »
Technically, SAAMI specs for Weatherby cartridges should include the freebore.

I usually start at the longest length which will feed from the magazine, and work back from there. Being close to the lands isn't a good setup for precision in any of my rifles, Weatherby or otherwise, so far, so I don't worry too much about it.
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Re: Bullet seating depth for Weatherby rifles
« Reply #3 on: January 12, 2019, 02:33:02 PM »
I will add to go to the reloading website of the bullet maker to get COL for a particular bullet in a caliber.I will use Barnes Reloading as an example as that is the one I am most familiar with for the Weatherby Mags.They have researched and tested.I have found their data to be very close and something to start with.
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Re: Bullet seating depth for Weatherby rifles
« Reply #4 on: January 12, 2019, 07:16:10 PM »
I will add to go to the reloading website of the bullet maker to get COL for a particular bullet in a caliber.I will use Barnes Reloading as an example as that is the one I am most familiar with for the Weatherby Mags.They have researched and tested.I have found their data to be very close and something to start with.

+1

Re: Bullet seating depth for Weatherby rifles
« Reply #5 on: January 12, 2019, 07:33:26 PM »
Technically, SAAMI specs for Weatherby cartridges should include the freebore.

I usually start at the longest length which will feed from the magazine, and work back from there. Being close to the lands isn't a good setup for precision in any of my rifles, Weatherby or otherwise, so far, so I don't worry too much about it.



You would think so but no, they don't. If I was to order a custom barrel chambered for a Weatherby .257 from someone like Lilja, I would need to tell them how much free bore I wanted.


SAAMI specs and drawings are available at https://saami.org/
Mark V Deluxe .257,6.5-300,300
Mark V Tactical 338 Lapua, .308
Tikka T3x Light 22-250
Ber B-14 HMR 6.5 CM
Marlin 1895 SBL 45-70
Win 94 30-30
AR-15 Match 5.56
AR-15 Match Wylde .223
AR-10 Match .308
WASR-10/63 AK47 7.62x57
Russian SKS 7.62x57
Turkish Mauser 8mm
UZI Mini Pistol 9mm
Barrett M82A1 50BMG

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Re: Bullet seating depth for Weatherby rifles
« Reply #6 on: January 13, 2019, 07:25:36 AM »
I will add to go to the reloading website of the bullet maker to get COL for a particular bullet in a caliber.I will use Barnes Reloading as an example as that is the one I am most familiar with for the Weatherby Mags.They have researched and tested.I have found their data to be very close and something to start with.


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Re: Bullet seating depth for Weatherby rifles
« Reply #7 on: May 09, 2019, 06:20:09 AM »
I typically start at mag length and work down from there as far as seating depth. In my experience, adjusting seating depths is effective in a weatherby even though they have the freebore. I typically do powder first, then go to seating depth as far as working up a load. I have found in my 300 mark v as little as .010 to .015 thousandths to make the difference between a 1.5 inch group to sub MOA.

Re: Bullet seating depth for Weatherby rifles
« Reply #8 on: August 17, 2019, 02:05:22 PM »
Agree with Terminator.
played around quite a bit with my mark v 257.
Best groups, under .4 were right at Barnes recommended col.