Jump to Lands Question

[Brandon05_88]

I've been searching for quite some time and haven't found an answer. I just check my 700 SPS-V in .243 for a jump to the lands with a 95 gr Matchking. Not what I was wanting to see. Bullet touches lands at 2.869" OAL. Max mag length to operate smooth is 2.825" OAL (2.830" is length of the internal mag). So is a 0.044" jump to the lands too extreme? Or should I just load them around 0.020" off lands (for initial testing) and forget the magazine? I plan on later using this load in tactical competitions, so that should be considered too. Thanks.

 

[vman]

Re: Jump to Lands Question

Welcome to the world of Remington.

Up to you really.

Try out max mag length and see how you go. Then take that same load and tweak it, kiss the lands and play with powder a little around your original node.

If you see a noticable difference then decide which to stick with.

 

[Rover31]

Re: Jump to Lands Question

save up the $, take it to a good smith for setback and a recrown. step #2 watch your groups shrink!
T

 

[redbullitt]

Re: Jump to Lands Question

My smks never really minded a little hop. If the gun is just a range/target, go ahead and single feed them. Barring modification, I would just go right with mag length, especially if you are hunting or doing any practical shooting with it.

I have loaded 308 rounds at the generic length 2.810ish just to keep handy so they will run in my semi or whatever else i could need. They have worked just fine in rifles where 2.875ish is close to touching the lands. The smk really doesnt seem to mind jump (vlds are another story...). I have shot some really nice groups with the short rounds and would not feel bad about shooting mag length in your situation.

As was said, play with the load a bit. Seat them to mag length and tweak everything a piece at a time. I wager you will get acceptable rounds before too long.

 

[Greg Langelius *]

Re: Jump to Lands Question

It depends. If you prize magazine feeding, then that should be your OAL goal, and the rest of the cards need to fall where they may. I also tend to think in terms of what might happen if my ammo got picked up by someone else.

If you're going to jump them, and I think it's preferable to do so from the viewpoint of potential pressure spikes; then I believe it makes sense to jump by a respectable bit.

Saying that the bullet touches the lands at a precise OAL is deceptive, bullet bearing surfaces and ogives will vary that ideal OAL by a considerable bit. I prefer to employ a 'fudge factor' and back off at least .010" to .015" from any nominal 'contact distance' OAL.

Greg

 

[ggmanning]

Re: Jump to Lands Question

Try out several ranges as outlined here:
http://02b0516.netsolhost.com/blog1/?m=200904

I am running some 105 Bergers at .120 jump in a .243 and they are lights out in that gun. When you find the best range of jump then fine tune as needed.

 

[Brandon05_88]

Re: Jump to Lands Question

Greg, I agree that I don't really want them closer than 0.015". That's why I was going to run this OCW test tomorrow at 0.020" off the lands. I would really like to use the magazine as I plan to hunt with this rifle some. I'm going to load them up to fit in the mag (2.825" OAL) and see how it turns out. My main concern was that 0.044" seemed a bit much to jump but, based on what some of you have said you were using, that doesn't seem like much. Thanks for the link gg. I plan on using that method after the initial test tomorrow. I'd rather save up for an action true-up and rebarrel than mess with the factory barrel. That may be some time now since I just got my first Nightforce 2 days ago. Lol Thanks for the input everyone. I'll jump back on here tomorrow and let you know how the test turns out. (95 SMK, RL22 38.5-42.5 gr, Lapua brass, CCI BR2 2.825")

 

[Nessal]

Re: Jump to Lands Question

I have seating them from .02" off the lands to jammed. Made no difference in my 700 at all. So now I just seat them all at the lands.

 

[jbailey]

Re: Jump to Lands Question

SMKs don't care if they jam or jump. One of the nice things about a tangent ogive is that they are not, typically, sensitive to seating depth. Keep them mag length and jumping!

 

[ggmanning]

Re: Jump to Lands Question

The only draw back from jammed in a hunting gun is if you have them jammed much they will tend to lengthen every time you unload the round.

 

[Hellbender]

Re: Jump to Lands Question

Both my .308's are jumping over 1/8", my 5R is closer to 1/4" (.200" jump) and both will shoot in the .3's off the bench.

My TRG-22 will shoot about anything you stick in it under 1/2 MOA and it is very long throated.

I think the whole "close to the lands" thing is not nearly as critical as chambering done straight and true to the bore with lead dimensions tight to the bullet.

Load to mag length and work the load from there, I bet it will surprise you. Remington's usually shoot better and better as a few hundred rounds go downrange and smooth the bore.

 

[Brandon05_88]

Re: Jump to Lands Question

+1 on the shooting better and better with more rounds. I shot about 100 rounds down it before she broke 1/2" 3 shot groups much less 5 shotters. Now with 288 down the tube, I've seen some nice 1/4" groups. Good point Hellbender on the chambering. I kinda wonder sometimes about how true my Remy is.

 

[spot69221]

Re: Jump to Lands Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hellbender</div><div class="ubbcode-body">...I think the whole "close to the lands" thing is not nearly as critical as chambering done straight and true...Load to mag length and work the load from there...Remington's usually shoot better and better as a few hundred rounds go downrange and smooth the bore.</div></div>

Seems about right to me, the only reason I choose to load .010 off the lands is to put more powder in there

 

[JRose]

Re: Jump to Lands Question

I had a GAP .243 with a long throat. At max OAL I was jumping around .050" with 115 DTACs. Gun grouped teenie tiny groups. I removed the blinder plates from the mags, loaded about .015" off the lands, never saw a difference in accuracy.

I try to load to about .015-.020" off the lands iff possible, but unless it's a VLD style bullet, I don't sweat it if I can't get it.