Touching lands /pressure increases

[Malxwal]

What is the likelihood of seeing pressure signs when loading to touch the lands. For reference, this is regarding my 6.5x47 using RL15 towards 39.0 grains, 123 Amax.

 

[onehole]

Nothing wrong with touching lands or into them,,,but,,,simple rule ,,,,work up powder load just as one normally would do observing pressure signs. Your question though and from memories of my time with a 6.5/47 I would say that would not be a load I would like to use just to see what happens,,,take care,,,,,O

[Malxwal]

Thanks. Perhaps quoting an exact load wasn't right; I was trying to convey that I would be using a charge of RL15 that was upper end.

[Blue Haze]

If it's a max load in tie rifle when you ate off the lands, then it will be over if you jam. But if your not at max then you may not notice.

 

Just make up 2 rounds that are backed off 1 gr,2 at -0.7, 2 at -0.3 then back to full load to make sure.

[Malxwal]

Cheers folks. The rifle seemed to prefer rounds being loaded closer to the lands,but I then realised the rounds were quite slow, little more than 2710fps from 37.6gr RL15 from a 22" barrel.

I'll see how it goes upping the charge at .010" off tne lands, then experiment as described, safely.

[gbal]

Malxwal, just some cmparative data on velocity effects-it's 260rem,as its SAAMI loads,so pressures etc are known and controlled (ditto MVs etc) 24" barrrel:200y zero , drop/drift inches 10mph wind and energy ft lb:

 

Nosler Nosler Partition 125 BC.449 @2950 300y 7/6.5" and 1533 ft lb

 

Remington Nosler Partition 125g .449@ 2875 300y 7.4/6.7" and 1449 ft lb

 

75fps reduced MV effects are ....modest.

 

gbal

[onehole]

Your 22 inch barrel will be robbing you of at least 100 fps or more I reckon compared to a 25/26 inch where you will see perhaps 2850/2900,,,,again from memory[didn,t keep my records] pretty sure I ran 120gn Amax 37.5//RL15 for 2850 ish in my 26 inch RPA and would have been close to lands for sure....This was a very accurate and safe all year round load and really no point in looking for more in my case.There are some very good examples and write ups on various 6.5/47,s on 6BRmm.com and you would find them in "Guns of the week" section,,,,,,,,,O,,,,,,,,PS,,,,,also from memory RL15 could be a bit of a dirty burn,,,,don,t be afraid to use the bronze brush with some vigour and a good carbon remover.,,,,,,O

[Malxwal]

Your 22 inch barrel will be robbing you of at least 100 fps or more I reckon compared to a 25/26 inch where you will see perhaps 2850/2900,,,,again from memory[didn,t keep my records] pretty sure I ran 120gn Amax 37.5//RL15 for 2850 ish in my 26 inch RPA and would have been close to lands for sure...

Yes, I have to accept that in opting for a shorter barrel there's a trade off with velocity, but unless I have a particularly slow barrel (Sassen 1 in 8.5, 4 groove) I would have thought I'd have seen more than 2710fps with 37.6gr RL15. The grouping with that load was good but not perfect, and got noticeably worse with distance from the lands. ES was good, so I suspect just trialing with more powder. The initial question could probably have been answered by trying varying OALs in Quickload, but I dont have a copy, yet.

[foxpig]

I'd say your velocity is about right from your barrel length. I'm getting 2940fps with 38.8gr rl15 from a 26 Krieger 8 twist.mag primers. Jumping 40 thou.

Funny thing was from 80 thou away and 10 thou jammed groups size was hardly changed.

[gbal]

Touching or even into lands will raise pressure-but not over safety levels,unless the actual load is already close to max. Seating Into lands eg can sometimes to used to ensure fire forming of a standard cartridge to the wildcat chamber,as in Ackley Improveds,but with a reduced load. to compensate and keep pressure safe.

 

gbal