Off the lands?

[ronc80]

I'm working on a couple recipes for my 7mm08. I've come across something that makes me go hummm. Of course I'm kinda new to a lot of this. My hummm moment is with a 150 grain nosler E-tip. Load data says 2.770 for coal. I have 2.9540 at the lands with this bullet. That's a big long jump. Do I dare come .002 to .005 of the lands? It still leaves .52" of projectile in the neck of the case. Also what does that do for the pressure inside the case at the moment of truth?
The line in the pic on the E-tip is whats left in case. At 2.770 the conallure is just showing

 

[hunter24605]

In my experience the e tip prefers a good bit of jump to the lands. I usually start at .050 and the sweet spot is usually between .050 to .100. Also measuring off the tip, I doubt you’ll be able to maintain .005”. There is to much inconsistency in the tips. For that much precision in your measuring, you need a comparator and be measuring cartridge base to ogive. Much more consistent in determining how far off the lands you are. On the e-tip it’s not really a cannalure, it’s a relief band. But it’s ok to be outside the neck. Not sure about nowadays, but the rule of thumb used to be to leave at lest 1 caliber size in the neck. So, for example, a 7mm you’d want .284 of bullet in the neck

 

[AFG270]

E-tips usually like a lot of jump, in my 25-06 I am .135 off the lands and when I had my 270 wsm I was more than that, I believe.

With E-tips I start .050 off the lands and go deeper if need be to tighten up the group.

 

[JD338]

E Tips do best at .100" off the lands.

JD338

 

[ronc80]

In my experience the e tip prefers a good bit of jump to the lands. I usually start at .050 and the sweet spot is usually between .050 to .100. Also measuring off the tip, I doubt you’ll be able to maintain .005”. There is to much inconsistency in the tips. For that much precision in your measuring, you need a comparator and be measuring cartridge base to ogive. Much more consistent in determining how far off the lands you are. On the e-tip it’s not really a cannalure, it’s a relief band. But it’s ok to be outside the neck. Not sure about nowadays, but the rule of thumb used to be to leave at lest 1 caliber size in the neck. So, for example, a 7mm you’d want .284 of bullet in the neck

I have a comparator I was just doing it to the tip for visual purposes. I'll start at .05 off to see what happens. Thank you for the information. It was very much needed. I was doing some 175 grain nosler partitions earlier and the jump was nothing like the e-tip. Figure I'd better get some professional guidance.

 

[DrMike]

E-Tips like quite a bit of jump, just like Barnes TSX & TTSX. It it the nature of monometallic bullets. As JD338 said, in my experience I almost always wind up at least 0.100 off the lands. I have been much more than that on a few occasions.

 

[RL338]

I’ve found Barnes coal to be very good on their bullets. They show 2.800” for their 150gr TTSX which would be a good reference point.

 

[TackDriver284]

You may get high pressure spikes with copper bullets if seating close to the lands. I would back off .050" or a tad more to start. Barnes recommends .050" off the lands.

 

[jimbires]

I've only used Barnes TSX in mono bullets . if I remember right my jump was 0.070" .

 

[Lazy Bushman]

First off, how does it shoot before messing around with trying to extend or seat deeper? I can honestly say that I have no idea how close or far any of my loads are from the lands. I start with the projectile sitting as far out as possible while still feeding well from the magazine and it I want to tune it, I may make incremental adjustments to seating depth even though as time goes on, the distance from the lands increases due to erosion.

 

[Charlie-NY]

My buddy shoots mono-metal bullets .250" off the rifling in his Weatherby Mark V. They shoot very well despite the BIG jump to the rifling. Just look for acceptable accuracy and normal pressure in a reload that fits in the magazine and feeds well. The amount of jump isn't that important.

 

[ShadeTree]

As was already mentioned several times, mono's like plenty of jump. Worked with a 300 WSM last week and TSX's that was running at .220 off.

2.800 is gonna be about your limit in most short action magazines unless you want to use it as a single shot. That is a long bullet in a 7mm-08. I'd venture to say you wouldn't want to go any shorter than 2.770 as you're already well below the neck and encroaching into the actual case body with the base of the bullet.

You can take your own measurements to verify, but you will likely find you do not have a whole lot of wiggle room with that bullet in a 7mm-08.

 

[ShadeTree]

BTW, not having much wiggle room does not make it a bad choice depending on your reasons and uses for picking that bullet. With the right powder and powder charge it will likely shoot just fine at the measurements of book length to magazine length.

 

[ronc80]

Hey all didn't mean to bail on this just got life
getting in the way. Broke truck broke 4 wheeler bow season and off course my as of today 16 year old son decided to try to hunt this year. He gave it a try a few years ago but the cold got to him. So on top of getting his bow set new arrows made and loading for his rifle because around here ya can't just go buy a box of factory rounds non to be had. If ya did find some there about $50.
So I did load up some e-tips at 2.856. Which is .100 off the lands. Haven't got out to my range to try them yet I'm running out of time but my plan was this Saturday. Both parents are getting moved into a constant care facility so still might not get out.
I really appreciate all the input and advise from all of you. I will hopefully let ya all know how I make out.

 

[ronc80]

Update: the e-tips didn't work all that well at .100 off the lands groups were 2" plus on the ones a tried. Had to stick with the 175 gr nosler partitions that where working good at book specs but wanted to get them better .002 of the lands was the sweet spot. This is the first pic. I also loaded some recipes up for my BLR 81 so my son could use it for hunting this year. Pretty good darn group for a rifle that never had grouping smaller than 2" with factory ammo.. we both had a flier but these both have a load that should work just spectacular for hunting.

 

[ElmerThud]

I found all the Nosler bullets I use like a long jump to the rifling. I never found one Nosler bullet performing satisfactorily seated close to the lands.
With a decent jump - awesome!

 

[ronc80]

I found all the Nosler bullets I use like a long jump to the rifling. I never found one Nosler bullet performing satisfactorily seated close to the lands.
With a decent jump - awesome!

Not sure about anyone else that shoots a tikka but this barrel likes slow. Groups always open up the more I load the powder in. This is only the second bullet I've tried shortening the jump. .002 of the lands .oo4 was about 1/4" bigger group with 40.5 gr of imr4350. The first bullet was the e-tip and I put them at .100 off the lands like was recommended by everyone that replied. It wasn't good at all so I just moved on to the nosler partitions. I have to go back and compare the e-tip results to my original results when it was at standard coal. Just haven't had time but it darn sure wasn't any better. Memory says the bigger jump was way better.
Now the browning BLR 81 likes fast kinda new that going in. It shot hornady white tail ok for what gun it is. 2" + groups. It liked hornady superformance better sub 2" groups. When my son was going through the ladder on my reloads the faster they got the better the groups got. So when we got to the last 5 I was still hopeful and it worked out. That was 40 gr h380 with a 154 interbond at the tip.

 

[SJB358]

E-Tips like quite a bit of jump, just like Barnes TSX & TTSX. It it the nature of monometallic bullets. As JD338 said, in my experience I almost always wind up at least 0.100 off the lands. I have been much more than that on a few occasions.

Same here. Seem them just come together like crazy when they get seated deeper.