Seating depth test before powder

[The big greasy]

I’ve been reading some say to do the berger seating depth test before finding a good powder charge. Questions are

1. Seating depth first?
2. Once found, does the seating depth stay good through testing different powders and charges?

 

[wapitibob]

Never, I set .020 off and leave it.

 

[The big greasy]

Never, I set .020 off and leave it.

Even for these fussy vlds?

 

[wapitibob]

Yep, shooting 195's right now in 2 different barrels, .020 off and haven't touched it. I don't have enough barrel life to do much messing around. I did the same with 180 vld's; it never made enough difference for me to continue. Guys swear by it though.

 

[Shooter Mike]

Never, I set .020 off and leave it.

How often do you clean your chamber and barrel?


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[wapitibob]

How often do you clean your chamber and barrel?


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Cleaned the STW after every range session and when I pulled it to exchange for a 7PRC. Cleaned the PRC after 3 shots, then 10, then at 90 when I switched from 180's to 195s. I pulled that barrel last week at 145 total, and will clean it in a day or so. I put the STW back on, shot 15 today and may leave it dirty and see how it does.

 

[Shooter Mike]

Cleaned the STW after every range session and when I pulled it to exchange for a 7PRC. Cleaned the PRC after 3 shots, then 10, then at 90 when I switched from 180's to 195s. I pulled that barrel last week at 145 total, and will clean it in a day or so. I put the STW back on, shot 15 today and may leave it dirty and see how it does.

That sounds like a very reasonable method. Would you agree that those who don’t clean their rifles until accuracy wanes would be better off with deeper seating depths? The way my mind sees it is, while 0.020 might work great, when that gap erodes, it changes pressure sooner and by a wider margin. That’s me just guessing without really experimenting. That said, with Bergers, I’ve had the best results being much farther off the lands. But it could have just been something with the one barrel I was loading them in. If I remember right, I’m thinking somewhere in the 0.080” range.


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[wapitibob]

I'm not a believer in waiting till accuracy goes away; it's a day late at that point. That's why I always kept it clean and with few rounds fired and uncleaned.

I burned over .120" out of the throat in the STW and never moved the bullet from the original .020 off. When I measured that .120", I was going to toss the barrel but decided to load it like a 28 Nosler, and moved the bullet out to again be .020 off those burned up lands, and it's been there ever since although I shoot it sparingly. That last move set the bullet boattail above the shoulder/neck radius and turned that barrel into a much better shooter. I would guess, based on earlier measurements that there is probably .150" burned out of that throat now, I can measure erosion after 10 shots.

The PRC is too early to tell where I will keep it. Expensive barrel and throat eating powder is going to make it a light use barrel.