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if you shoot "jammed" loads,

762plinker

how much neck tension are you using ?
i am a jump shooter with little luck in jam.
i have a cartridge i may try jam based on some comments. i use lite neck tension, what do i need to do if g0ing to a jam load.
( guessing between .005 and .015 jam)
thanks
 
762plinker said:
how much neck tension are you using ?
i am a jump shooter with little luck in jam.
i have a cartridge i may try jam based on some comments. i use lite neck tension, what do i need to do if g0ing to a jam load.
( guessing between .005 and .015 jam)
thanks
Click to expand...
I've had more luck than not while jamming. Since it's difficult to quantify how much tension you need I'll just say this. Use a bushing small enough to allow you to engage the rifling to the point where the marks are at least square before the bullet will move in the neck. I'd use a little more just to be sure. Once you have the bullets seated to that point and you start testing seating depth, you have really only one direction to work in...out from the lands. Depending on cartridge and bullet, I'd move no more than .003 at a time.

Part of the beauty of this approach is the simplicity, in that you can only go one direction. The rest is that possibly near 95% of the time, my best seating depth is between there and .010 off of touch. Several thou difference there but most often, it'll be between there and just touching, to narrow it down a bit more.

If nothing else, being jammed lessens your dependency on neck tension being identical because the neck will open up before the bullet can move. As with anything...test...test and test some more. Different bullet styles often prefer more or less jam, etc. Only one way to learn for sure and the internet is chock full of good intentions and little testing. Don't be that guy.
 
Like SPJ is saying, there is jam and then there is jam...

For example, bullets are not all made with equal ogive geometry, or jacket materials, and some are hybrids such that the part of the bullet that engraves is a different curvature than the nose. And then there is the matter of the reamer differences, rifling differences, and the throat wear. All of which mean that context matters.

You can even elect to soft-seat the bullets such that chambering them will only jam them to the limit of the neck friction force and then they slip further into the neck. This method works for some folks, but I have seen folks damage their lugs playing with the method before they realize what galling can do to their lugs.

If you play with jam, be sure to keep your chamber and lug area very clean and keep the bolt lugs lubricated.

Since different folks will call the touch point differently, the same can be said for their neck tension values and how much they are calling a jam.

Practice in your shop with dummy cartridges before you load anything and get used to what can happen with your present prep method and different seating depths. When you play around with increasing the amount of NT or jam, you can then set your experimental limit for live loads. Just be very careful with your lugs and think ahead to how you will shoot in the field so that you are realistic about how much torque and force you want to place on your bolt when chambering at a maximum.

With luck, your rig will show you good performance without being dramatic or requiring heroic forces on the hardware.
 
gunsandgunsmithing said:
I've had more luck than not while jamming. Since it's difficult to quantify how much tension you need I'll just say this. Use a bushing small enough to allow you to engage the rifling to the point where the marks are at least square before the bullet will move in the neck. I'd use a little more just to be sure. Once you have the bullets seated to that point and you start testing seating depth, you have really only one direction to work in...out from the lands. Depending on cartridge and bullet, I'd move no more than .003 at a time.

Part of the beauty of this approach is the simplicity, in that you can only go one direction. The rest is that possibly near 95% of the time, my best seating depth is between there and .010 off of touch. Several thou difference there but most often, it'll be between there and just touching, to narrow it down a bit more.

If nothing else, being jammed lessens your dependency on neck tension being identical because the neck will open up before the bullet can move. As with anything...test...test and test some more. Different bullet styles often prefer more or less jam, etc. Only one way to learn for sure and the internet is chock full of good intentions and little testing. Don't be that guy.
Click to expand...
i have done a ton of shooting and testing..just very little in the jam side of loading...which is why i asked,i know where touch is and have done testing off of touch, but not happy so looking at going jam and trying some more
 
RegionRat said:
Like SPJ is saying, there is jam and then there is jam...

For example, bullets are not all made with equal ogive geometry, or jacket materials, and some are hybrids such that the part of the bullet that engraves is a different curvature than the nose. And then there is the matter of the reamer differences, rifling differences, and the throat wear. All of which mean that context matters.

You can even elect to soft-seat the bullets such that chambering them will only jam them to the limit of the neck friction force and then they slip further into the neck. This method works for some folks, but I have seen folks damage their lugs playing with the method before they realize what galling can do to their lugs.

If you play with jam, be sure to keep your chamber and lug area very clean and keep the bolt lugs lubricated.

Since different folks will call the touch point differently, the same can be said for their neck tension values and how much they are calling a jam.

Practice in your shop with dummy cartridges before you load anything and get used to what can happen with your present prep method and different seating depths. When you play around with increasing the amount of NT or jam, you can then set your experimental limit for live loads. Just be very careful with your lugs and think ahead to how you will shoot in the field so that you are realistic about how much torque and force you want to place on your bolt when chambering at a maximum.

With luck, your rig will show you good performance without being dramatic or requiring heroic forces on the hardware.
Click to expand...
i load to a formula..which includes a known length....will continue with that
 
I jam . Each gun has too many variables to be definitive as to neck tension , bullet ogive , composition, barrel leade angle , freebore ballseat etc . Use a majic marker and some dummy roumds . Start a jam of about .010 be sure to test so you can eject a loaded round . Dumping a case of powder in an action isnt fun .
 
762plinker said:
i have done a ton of shooting and testing..just very little in the jam side of loading...which is why i asked,i know where touch is and have done testing off of touch, but not happy so looking at going jam and trying some more
Click to expand...
Touch is a pretty long way from "square" marks, depending a lot on bullet shape. It might be .010 or .060. And depending on how you establish "touch", too.
 
Ggmac said:
I jam . Each gun has too many variables to be definitive as to neck tension , bullet ogive , composition, barrel leade angle , freebore ballseat etc . Use a majic marker and some dummy roumds . Start a jam of about .010 be sure to test so you can eject a loaded round . Dumping a case of powder in an action isnt fun .
Click to expand...
Yessir but it depends on the discipline. In BR, we can dump a round without extracting it, except on very rare safety occasions. I seat to what shoots best. The rest be damned. Hunting rifle or different application would be a different story...agreed. Even still, I'm not afraid to seat at soime amount of jam, even in a hunting rifle. I just wanna be 100% sure it won't pull a bullet and dump powder everywhere.
 
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But isn't everything on google?;)
If not...then what...or it's too much work...etc. Some things require work

Years back I had a retail store front and kept BR rifles on display. About every day I had people ask things like how much it cost to get into the game. At the time, about $5k would get you started with everything. I'd tell them that and most would run backward. I'd look outside at what thet were driving. Many times is was a $80k pickup pulling a $40k boat and I'd just tell them...they'd suck at it anyway because you have to want it. You can't buy it and judging by your truck and boat...you can afford it but clearly, you don't want it bad enough to NOT suck at it. True story! Grumpy old gunsmith! Lol!

I mean...$120k worth oy toys and run backward from a $5k equipment investment? You gotta want it. If you don't, then save your money.
 
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