Bullet touching the lands or 2000th back?

[Lenny Foffa]

Excellent post!

Thank You Pete!!! Lenny

 

[deweyduck]

Although some rifles like the bullet touching or jammed in the land, there is always the chance that the bullet will pull out, when extracting a loaded round. You must have very consistent seating depth to prevent dumping your powder into the action. This is why you hardly see the bullet jammed in hunting rifles.

My Win 70 in 7RM likes it jammed about .002 but after pulling a slug, I only do .001 jump. But that is still too long for the mag. However, 1 round in the chamber and 1 round on top of the mag works fine. And the bolt will cycle that round on top perfectly. So that gives me a 2 shot rifle. Then I put 2 short ones in the mag first and that gives me a good 3rd followup shot if necessary; so far, knock on wood, I've not used even the 2nd shot.

 

[Steve Sheasly]

The 340 Weatherby I developed loads for has .406 of jump. I put 3 bullets through the same hole at 100 yards. Do what works Roy Weatherby made some pretty hot loads early on. To mitigate the pressures he machined long throats and massive jump. Accubond bullets like jump. I am shooting 300-grain Accubonds with 78.5 grains of IMR4831. You will not find this load in any book. I have talked to both Nosler and Hodgen. Hodgen does not have a pressure barrel for a .340WM but Nosler does. But since this is not a common rifle they may not ask the lab to check the pressures of this load. But, I have no pressure signs. Probably owing to the massive almost 1/2 jump.

 

[Tulsa Reiner]

This is a local matter, and not a matter of opinion, but of tested best.
Do you mean 2" or .002", or something else?

I assume he means 2 x1000ths, ie 0.002"

 

[Mikecr]

I assume he means 2 x1000ths, ie 0.002"

I was just asking for confirmation. It's possible to matter.

 

[Toydy]

I just purchased a Nosler Long Range Carbon Rifle, chambered in 28 Nosler, and have started working on a load using the 175 ELDX bullet. I tried Norma 217 powder but was unable to find a consistent charge weight. The velocities were all over the place. I tried Retumbo and have a good velocity node around 81 grains and velocity just over 3200 fps.
Having read the discussion above, I can see it may take many rounds to find the right jump. Does anyone have experience with this bullet, powder, and cartridge combination that may be helpful in minimizing the number of rounds down the barrel and still find an accurate load.

I just shot 81 grains retumbo 175 eldx into .28

 

[elf]

I usually have them barely touch in competition rifles, but seat hunting bullets much deeper so that I have no worries about having a jam problem.

 

[Angelo Campana]

I agree with just about everyone here, it is a matter of trial. I don't like any "tickle" of the lands to the bullet. And for the most part, I start with a .020" jump. Test fire at 100 Meters, 300 Meters, 500 Meters. Then I measure the results for THAT specific round that I loaded. From there...it's all experimentation. Really Good POST here fellas. Wish I could spend more time on this Forum, but I travel a lot. Whenever I do get the chance, or have a question....this Forum usually has the answers.
Thanks!

 

[freddiej]

There seems to be a question of varying opinion on whether to have a 2000 th jump to the lands and option of bullet touching the lands for best accuracy. What's everyone's thoughts here?

Skip,
I agree with a few others here. there is no one absolute answer. for example I have 4- 270 caliber rifles. Two 270 Winchesters, two 270 WSM's. My Tikka loves light Barnes TTSX and TSX slugs about 0.035" off the lands (0.065" shorter than loading manuals specs) this gun also loves to over pressure everything you shoot out of it. AKA very small chamber so it gets light powder charges and delivers pin point (0.375" approx edge to edge/ 0.098" C to C) accuracy. my Model 70 Featherweight carbine loves Barnes (TSX 110 grain) and Berger (130 VLD hunter) slugs. TSX slugs 0.075" off the lands, berger it loves them 0.015" off the lands.
My Kimber 8400 Montana rifle loves Nosler (140, 150) 0.015" off lands, Berger (140, 150) 0.010" off lands.
My Winchester 70 270 WSM loves nothing.. this gun would not put 5 rounds on paper if it's life depended on it... no, not really. it likes 160 grain slugs but it depends on the day of the week where the slug should be off the lands, what powder, what charge, and what brass you use. found out the barrel has a soft spot in it and it is off getting rebarreled in Oregon.
Most every other gun I own loves what ever I shoot through them between 0.010" to 0.025" off the lands. That is lead core. when I use Barnes they usually want 0.050" to 0.065" off the lands. I tried the full 0.100" off the lands and regretted it.

Just remember this axiom, the closer to the lands; the higher the pressure for the same powder charge and down load accordingly. If I still had the pic of Craig's gun on my computer I would post it. 7MM Rem Mag, pretty hot H-1000 powder charge, Barnes 150 grain TTSX-BT, 0.005" off lands.. KABOOM! no more Rem 700 Alaskan rifle, no more Leupold scope, Bolt grenaded, Ring grenadaed, barrel stem grenaded, stock vaporized. Remington told him it took a minimum of 500,000 PSI to blow the gun like that. everything blew straight up. good for him.. not good for his trip to Montana for Elk season.

 

[thethirdpig]

Experiment! End of story. Try .001, .0015 .002. touch, etc.

 

[SealT5]

There is no doubt a bullet can shoot good at touch but IMO it can be too finicky. 5 thou jammed or jumped is ok.

FWIW I prefer a jump in all my rifles.

Like pig said. Experiment!

Joe