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Seating bullets into the rifling

Personally, I’ve never found a single rifle I shoot for competition targets to shoot better with jumped bullets as opposed to shooting them .009-.018” off hard jam (using 1.5-3.5” of “neck tension”). I have tested lots of bullets out to as far as .120” off the lands and never found one that will consistently shoot. You may find a few small groups at a particular distance off the lands, but I think you’ll find as many large groups at that same distance. People can disagree all they want, and I’m sure some will, but having firing literally 1000’s of data points I could never convince myself this fallacy holds true.
Dave
Years ago one of the guys that competes gave a review of seating depth for the new, at the time, Sierra 30 cal. 195 gr TMK bullet. He found .005 off was the spot. I tried it and it was the only place that worked for me also. My question is, as the barrel gets dirty that distance shortens from fouling. but it did not matter to me at the time. If you jam a bullet in a clean barrel, at some point after a few dozen rounds, won't that be really jammed and you need to force the bolt closed to chamber a round? I did a jam length test between a clean barrel and a dirty barrel and they were not the same length in my rifle.
 
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Personally, I’ve never found a single rifle I shoot for competition targets to shoot better with jumped bullets as opposed to shooting them .009-.018” off hard jam (using 1.5-3.5” of “neck tension”). I have tested lots of bullets out to as far as .120” off the lands and never found one that will consistently shoot. You may find a few small groups at a particular distance off the lands, but I think you’ll find as many large groups at that same distance. People can disagree all they want, and I’m sure some will, but having firing literally 1000’s of data points I could never convince myself this fallacy holds true.
Dave
Dave,
I too have found exactly the same thing! Many many times, .009 into the rifling is the one to beat. So now, I just start there and have only one direction to go seating wise. This is way, way to simple for many people, and they will have to start at .020 off the rifling just to make it awkward! I have no clue why, and most times neither do they. For some reason it cannot be this easy, it just can't be! Lmao. Carry on men and shoot straight.
Paul
 
I am confused by the two posted above. (boltfluter & steve donlon)

one post recommends .005 OFF and one recommends .009 INTO

Second bit of bit of my general confusion regards anytime someone says an amount INTO the rifling. How can something be MORE than into the rifling? Does this mean hitting the rifling and pushing the bullet further so its engraving itself into the rifling or back in the case?

My current rifle has a hard jam at 1.7565

so
.005 off would be 1.7515
and
.009 into would be 1.7655 ???

I have a new barrel and I just loaded some at these two measurements:
20 ea = jam @ 1.7565
20 ea = off @ 1.7465 (.010 off)
 
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finding a "touch point" with a bullet you're going to shoot is a good reference starting point in seating depth tuning
Wheeler method is recommended, then test into the lands (jammed) or away from the lands (jumped) let the barrel tell you what it wants.

 
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Thanks for the clarification. For finding touch I tend to favor the Wheeler method. https://www.wheeleraccuracy.com/videos
A friend has used that and then, using that measurement as a reference, played with his Hornady tool technique until he could reliably duplicate it. On the Modified cases, they are usually shorter, head to shoulder, than a fired and properly sized case. I always measure both and add the difference to what I get from the factory modified case.
^^^^^ This
 
Terminology is always the issue when this old topic comes up. Some people define jam as any dimension where the bullet is in contact with the rifling even though it is highly possible to move the bullet further into the lands. Other people define jam as the maximum distance a bullet can be into the lands at a given neck tension.

I rely on the latter and it has worked great on multiple guns and many barrels because when I start at that point, there is truly only one direction to go to arrive at seating depth nirvana. This simplicity is the beauty of it. The Tony Boyer book explains this better than me, but it is really easy to figure out and a great place to start load development for a BR rifle in particular.
 
More recently, I want to know both, since my seating depth is usually between them and I want to know what I have to work with, and how close to jam I am.
Agreed. Over the last couple years I have been using the Mike Ezell tool to find touch. Works like a charm on any barrel that is sitting on the shelf. I like data points to work with.
 
I read on HERE ( Old Searches ) that, the Best Accuracy from, Sierra 6MM, 107 gr. MK's were at, "Jam" PLUS and They, were,.. RIGHT !!
I can't exactly tell, How much "Jam" I'm using, as the Little Skid marks on the Bullet ARE Tough for me to, Measure,.. But, I can see that, they are, anywhere from, .010 to .020 and THAT,.."Works Well" for, Me !
I Reduced the Powder, a 1/2 grain off, Max and,.. Blammo !
It's my most Accurate, Load for, Steel Plate, Practice Fun !
 
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Agreed. Over the last couple years I have been using the Mike Ezell tool to find touch. Works like a charm on any barrel that is sitting on the shelf. I like data points to work with.
I am not familiar with Mike's tool. Could you favor us with one or more pictures? Also, have you seen the tool that is available at PMA Tool? It is like a very thin shell holder on a rod, that clears a cone breach and fits inside the counterbore of a Remington. With it you can do the test that Speedy made a short video about.
 
Dave,
I too have found exactly the same thing! Many many times, .009 into the rifling is the one to beat. So now, I just start there and have only one direction to go seating wise. This is way, way to simple for many people, and they will have to start at .020 off the rifling just to make it awkward! I have no clue why, and most times neither do they. For some reason it cannot be this easy, it just can't be! Lmao. Carry on men and shoot straight.
Paul
I did find that my girlfriends new 7PRCW shot the best at .020” off the lands. This is the first competition rifle we have ever found this to be true. When I talked with Alex Wheeler he said with the 7PRCW reamer he recommended and the Berger 180g bullets, there is generally a sweet spot about .020” OFF the lands.
We tested it from hard jam + .006”, all the way back to .100” OFF the lands; and wouldn’t you know it, the most consistent and smallest groups were at .020” OTL +/- .005”. Great groups all the way from .015” OTL to .025” OTL
We settled on .021” OTL

Dave M
 
I am confused by the two posted above. (boltfluter & steve donlon)

one post recommends .005 OFF and one recommends .009 INTO

Second bit of bit of my general confusion regards anytime someone says an amount INTO the rifling. How can something be MORE than into the rifling? Does this mean hitting the rifling and pushing the bullet further so its engraving itself into the rifling or back in the case?

My current rifle has a hard jam at 1.7565

so
.005 off would be 1.7515
and
.009 into would be 1.7655 ???

I have a new barrel and I just loaded some at these two measurements:
20 ea = jam @ 1.7565
20 ea = off @ 1.7465 (.010 off)
What ever works for your rifle. I just saw that the fouling keeps the bullet further away from the lands on one hand but also keeps the bullet from going forward into the lands for a seating depth test. And for me, it did cause me to load a batch of ammo that was outside of the parameters of where I needed to be because I had a false jam reading from the fouling with a new batch of bullets.
 
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