Jamming into lands???????

[Chappy6mm]

I've been trying to get some Berger VLDs to shoot out of my 6.5 WSM and I've been seeing that many reloaders say to jam them into lands. On one topic on this sight the poster said to jam .010. How is that possible? Wouldn't the bullet just be pushed back into case neck? It seems that there would be just one length where the bullet would be touching the lands and not actually .010 into them. Explain this to me please.

 

[dmoran]

The term "Jam" gets thrown around for anything from slight contact to a definite max engagement. Betting what you read was someone referring to .010" into the rifling and still short of max engagement (hard jam).

 

[Erik Cortina]

I agree, jam gets used incorrectly often. You are correct, you can not jam a bullet longer than jam.

I always stay away from jam, this way you don't run the risk of sticking a bullet in the lands. You can find an accurate load away from jam.

 

[mac86951]

My 7mmSAUM prefers a 0.040 jump to the lands with the Berger 180s (7mm). I stay away from anything beyond a light "touch" simply due to the situation where you might need to remove chambered but not fired round. I'd rather not have the bullet stay behind and the powder dump.

-Mac

 

[L.Sherm]

I could not get 140VLDS to shoot in my 6.5WSM touching the lands if I remember right they were somewhere around 10 thou. off the lands i'm not home right now to look

 

[jimbires]

I think you will find these articles interesting .


http://bulletin.accurateshooter.com/2009/03/berger-tips-for-loading-vld-bullets/


http://www.bergerbullets.com/wp-content/uploads/2013/03/COAL.pdf

 

[BradY]

See I have had good results jamming hybrids and jumping VLD's. My 260Imp actually shoots the same load with either hybrids or VLD's 10 thou past touch into the lands. Proved it at 900m- same elevation and windage. That barrel is being kept for special occasions.

 

[NCVarhtr]

Several year ago, I went to Virginia outside of Harrisonburg and met Tony Bowyer. I was taking his shooting/reloading course. I ask him about neck tension and after we checked the difference between a sized case and a loaded case, he was using .006 of neck tension. In his book, I think he say that he uses .004. Anyway, he jammed the bullet in the lands far enough to plainly see the rifling marks. He wanted the length of the rifling mark to be about the same as the width of the rifling mark. You can correct a lot of problems (and get some very tight groups) by seating in the lands if you can find the right amount to jam them in.....In my experience, tangent ogive bullets have worked well in the lands while VLD bullets seem to work well off the lands,...Of course, nothing here is "Carved in Granite" ...It takes careful experimenting and testing both in and off to find what you are happy with...

 

[searcher]

For those wanting to jam their bullets but don't for fear of dumping a powder charge by pulling a bullet out when unloading an unfired round - moly or other available bullet coating processes minimize the chance of this occuring - if not eliminate it completely. In the loads I use where I jam - I use moly coated bullets and have not had a "powder dump" since.

On the depth issue, those using very light neck tension often refer to their depth of jam - yet most often, they are in fact simply bringing the bullets to a uniform rest against the lands, referred to as a "soft seat"- and not pushing them into the lands. It is a bit of a stretch to expect, as you can imagine, a bullet being driven .015" into the lands with ".001" neck tension.

 

[expiper]

well now that we are all in a "jam",,,,as said earlier the lil' marks on the bullets tell it all when "jamin",,,,these marks tell you that you really are tuching the lands and the width to length ratio tell just how hard,,,I like to use lots of neck tension and never worry about pulling a bullet,,,if I want to "jump" em I seat the bullet to where the marks disappear and call that "zero" and then try to use a minimum of .010-.020" jump because of bullet variations which when trying to seat so close it may make one touch and then two or three not and then one touch again,,,,and you know what that can do to accuracy,,,,I think that the type/speed/ammount of powder has more to do with proper ignition (good SD/ES)....always remember that just because a PPC with 68 gr bullet and N-133 powder likes a certain ammount of jam/jump that doesnt mean that a .284 with a 180 gr VLD/Hybrid and 4350 powder will be the same,,,usually as the cal increases so does the bullet weight and the FB ,,,and the powder slows down,,,,the gun will tell you what it likes,,,Roger

 

[dkhunt14]

I totally agree with what you said Roger. You couldn't said it any better. Most of my guns really like the 10 in. Matt

 

[Joe Maisto]

I agree, jam gets used incorrectly often. You are correct, you can not jam a bullet longer than jam.

I always stay away from jam, this way you don't run the risk of sticking a bullet in the lands. You can find an accurate load away from jam.

+1

 

[expiper]

Matt... yep....I like em .010-.015 in(with bullet slightly "coined") or .010-.015 out ,,,orrrrr wayyy out,,,.050-.080"...Roger