BiB bullets question?
- Thread starter TrxR
- Start date
Looks like a 10 ogive and I believe those were on a 1" and confirmed on his website as such (just checked). I shot the 7's in both 118 on the 1" and 112 on the .925's and know plenty of people who shot the 10's...they are ass kickers!
If you ever get a chance to talk to Randy grab a pen and paper and listen closely - he has been there and done it!
If you ever get a chance to talk to Randy grab a pen and paper and listen closely - he has been there and done it!
R.G. Robinett
"That'll never work."
^^^^^ They were from the January 2019 set-up: N10 indicates ten ogive. The 118-tens "like" JAM and neck-tension.
RG
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^^^^^ They were from the January 2019 set-up: N10 indicated ten ogive. The 118-tens "like" JAM and neck-tension.
How much neck tension? .003-.004? and how much Jam?
R.G. Robinett
"That'll never work."
I'm not Randy (Randy can be thankful for that
) but here's my approach:- A bushing .004 under what the neck measures over the pressure ring of the seated bullet
- Seating depth .020 longer than when the rifling marks just disappear when using the stripped bolt method of checking seating depth....what we call a .020 'jam/seat'. I've also started with Randy's recommended .030 seating depth.
When using the stripped bolt method, use the .004 under bushing. If the bullet sticks and pulls out of the neck, make sure make sure to resize the case neck between each checking as you need that neck tension and consistency.
With the .020 jam/seat and the .004 bushing, I just tune it with the powder measure until it shoots 3 shot groups as small as it can. Then, with that powder charge, I back the seating depth up .005 at a time and shoot 3 shot groups. With the seating depth that shoots best, I'll shoot several 3 shot groups to see if it's consistently small. If it is, I go right to a 7-8 shot group at 100 to confirm the center of the group stays stable. With some of the powders like LT30, based on what I've been hearing....I'd lighten up the neck tension in steps of .001 after establishing the seating depth it likes. Other than that, I just leave the .004 bushing in with H4198.
Over the years, I've found that a well built .30BR/30X44/30X47, etc. (assuming a correctly dimensioned chamber) will easily tune up this way. Normally, I'm done in a little over 30 rounds (excluding the 7-8 shot groups).
For what it's worth.... -Al
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I'm not Randy (Randy can be thankful for that
- A bushing .004 under what the neck measures over the pressure ring of the seated bullet
- Seating depth .020 longer than when the rifling marks just disappear when using the stripped bolt method of checking seating depth....what we call a .020 'jam/seat'. I've also started with Randy's recommended .030 seating depth.
When using the stripped bolt method, use the .004 under bushing. If the bullet sticks and pulls out of the neck, make sure make sure to resize the case neck between each checking as you need that neck tension and consistency.
With the .020 jam/seat and the .004 bushing, I just tune it with the powder measure until it shoots 3 shot groups as small as it can. Then, with that powder charge, I back the seating depth up .005 at a time and shoot 3 shot groups. With the seating depth that shoots best, I'll shoot several 3 shot groups to see if it's consistently small. If it is, I go right to a 7-8 shot group at 100 to confirm the center of the group stays stable. With some of the powders like LT30, based on what I've been hearing....I'd lighten up the neck tension in steps of .001 after establishing the seating depth it likes. Other than that, I just leave the .004 bushing in with H4198.
Over the years, I've found that a well built .30BR/30X44/30X47, etc. (assuming a correctly dimensioned chamber) will easily tune up this way. Normally, I'm done in a little over 30 rounds (excluding the 7-8 shot groups).
For what it's worth.... -Al
So basically your wanting to find the spot where the bullet is just touching the rifleing then add .020 to .030.
"Seating depth .020 longer than when the rifling marks just disappear when using the stripped bolt method of checking seating depth."
Don't work forward to find where they touch.... work backward to where they just disappear.
Alex Wheeler has an excellent video of his process which is close to what I do. I like to 0000 steel wool the bullet to see the marks but that's neither here nor there.
https://www.wheeleraccuracy.com/videos
Do you start with the bullet in the case just enough to hold it? Do you you use the same bullet for the whole process? Do you move back .001 each time?
mwezell
Mike Ezell
I just start with heavy neck tension and a long seated bullet. I work backward from there, especially on the "little thirties". Most of the time they like it hard jammed. The 6's, I usually start around a square mark on the lands but many times they end up shooting best at near just a solid touch point. I don't really care how I get to the best desired depth. I find the wheeler method to work but to be more trouble and ultimately, other than conversing online to compare data, I don't think it matters how you get there. Yes, if everyone used his method, we could all come up with good comparative results that are easy to compare to one another but ultimately, it's just a means to an end that I won't likely be at when I find the best spot in multiple bbls...they are all likely a bit different anyway. It doesn't matter how I got to it. Clear as mud, right? Lol!
I hear 'ya, Mike.
The late Dick Wright authored an excellent article in P.S. about using the stripped bolt method. And Tony Boyer's book explains it very well, too.
On these .30s, a hard jam/seat and fairly heavy neck tension is always where I suggest people start. You may not ultimately end up there but using this method you only have one way to go.
As much as this advice has been shared by Randy, yourself and others....you'd think it would be part of '30BR 101'.
It's only been 20+ years, now!
Good shootin', buddy! -Al
The late Dick Wright authored an excellent article in P.S. about using the stripped bolt method. And Tony Boyer's book explains it very well, too.
On these .30s, a hard jam/seat and fairly heavy neck tension is always where I suggest people start. You may not ultimately end up there but using this method you only have one way to go.
As much as this advice has been shared by Randy, yourself and others....you'd think it would be part of '30BR 101'.
It's only been 20+ years, now!
Good shootin', buddy! -Al
Just seat the bullet excessively long....say .030 of the base into the neck. No need to go .001 at a time at first...more like .005 to .010. Once you start doing this, you'll get a feel for it. Polish the bullet with 0000 steel wool each time so you can see the engraving of the lands clearly. As the bullet gets further down in the neck, the marks will start to look different and the closing force will be less. If the bullet sticks in the barrel, just pop it out with a cleaning rod or a wooden dowel and reseat it. No need to use a new bullet each time.
Once the marks get real faint and just barely fade away, record that seating stem length. That's your 'touch point' for that specific bullet only. Repeat this for each bullet you will be shooting in that barrel so you can quickly and easily change from one bullet to another. Now you can just make the seating stem .020-.030 longer and you're ready to go for your initial testing. Use shims under the seating cap (Wilson style seater) or just just adjust the stem length to change seating depth.
Just one way to do it. It's stupid-simple....which works for my brain.
Good shootin' -Al