Finding the distance to the lands

[Heym SR20]

IMHO the reason for the bullets to be on the lands is to ensure consistent and even pressure build up as the powder starts to burn and before the bullet starts moving. I understand one Bench rest shooters technique is to load bullets long with minimal neck, the bullets are then seated on the lands as the bolt is closed. This gives the same initial resistance for each and every shot.

This is fine for benchrest shooting. But as soon as try to unload a round, the bullet remains seated in the lands and powder goes everywhere.

I would suggest forget chasing the lands. Load bullets to the designed cartridge overall length. As a final stage of the loading, apply a decent crimp to the case.

A good crimp holds the bullet firmly in place. This makes the round withstand normal everyday use. And when it is fired you get consistent pressure build up before bullet starts moving.

 

[DavyG]

IMHO the reason for the bullets to be on the lands is to ensure consistent and even pressure build up as the powder starts to burn and before the bullet starts moving. I understand one Bench rest shooters technique is to load bullets long with minimal neck, the bullets are then seated on the lands as the bolt is closed. This gives the same initial resistance for each and every shot.

This is fine for benchrest shooting. But as soon as try to unload a round, the bullet remains seated in the lands and powder goes everywhere.

I would suggest forget chasing the lands. Load bullets to the designed cartridge overall length. As a final stage of the loading, apply a decent crimp to the case.

A good crimp holds the bullet firmly in place. This makes the round withstand normal everyday use. And when it is fired you get consistent pressure build up before bullet starts moving.

It’s just as well we aren’t living in medieval times. You’d be put into stocks for such a blasphemous remark.

DG

 

[Stalker62]

I have done the 'hard yards', when it comes to loading and 'chasing the lands'.

My results in a


Stalking = no real advantage.

Target = there is an advantage to be gained. Most combinations have a 'sweet spot'. The truth is that such finite advantages are superfluous with a shooter as 'average' as I am.
How deep down the rabbit hole do you want to go?




Yewtree non-lead. These really like a long jump to the lands (0.030").




The only tests I undertook, where it really did make a difference at stalking distances.




Just hours of my life, I am never going to get back...

 

[Mungo]

I've read several different techniques for finding the distance to the lands. I've not heard of anyone doing the following and I'm wondering why not.

I loaded some cases with the bullets protruding as far as I could manage. I then chambered a round. I was expecting, from what I had read, the bullet to be retained in the rifling. I intended to tap it out and then keep trying with shorter and shorter COAL until it just didn't get stuck in the rifling any more. What actually happened was that the bullet was pushed back in the case as I closed the bolt. I did it three times and the resulting COAL was very consistent. It seems to me that I've found the lands with sufficient precision at this point and doing anything more complicated is unecessary.

The rifle is a .223 Howa. I'm workiing up a load for PPU 75gr HPBT match bullets. I'm intending to use them for CSR competitions - which is not a discipline for which ultra-accurate rifles/loads are essential (although more accuracy is always good, obvs). I'm messing around with COAL because I've struggled to get anywhere near 1 MOA so far.

If you’re struggling to get to 1 MOA, fooling around with seating depth is not going to solve your problem.

 

[HandB]

It's a good question. I have gone down many rabbit holes on this topic but as time has gone on I have realised that other factors such as my trigger control and wind reading have way more effect on group size than bullet jump. So I have regressed to seating to bog standard overall lengths (e.g., 2.8 OAL inches for .308) and it produces excellent results as long as I do my part, so when I acquire a rifle these days I don't bother about finding distance to lands anymore.

 

[Edinburgh Rifles]

no-one is measuring 6 thou on an angular surface with calipers with any degree of accuracy

you can throw a 2-5 thou error on calipers with variance in wheel torque

 

[GDhunting]

What twist rate howa do you have? Also if you are looking for accurate id try something other than PPU
What does the howa shoot like with other factory ammo such as Nosler 77grain or federal gold medal 69 grain?

 

[old 30-06]

I think you lot are overthinking the whole thing ! Take it back to basics.......this is after all, stalking forum. Keep it simple. Find a brass/powder/bullet combination sufficient for your purpose. There are plenty of "recepies" in all the loading books. Please do not try to invent the wheel. Forget MOA'S, MilRads, chasing the lands, and all that other mythical stuff. Get a one inch group at 100 yards and go out shooting.

 

[urban]

no-one is measuring 6 thou on an angular surface with calipers with any degree of accuracy

you can throw a 2-5 thou error on calipers with variance in wheel torque

You might think so. But I have checked by measuring a set of loaded bullets multiple times and I get consistent results each time to +-0.02mm (+-0.7 thou i.e. 1.4 thou variance). The idea that you can't measure to 0.15mm (6 thou) with calipers is....surprising to me.

 

[urban]

If you’re struggling to get to 1 MOA, fooling around with seating depth is not going to solve your problem.

I worry that you're right, and there's something wrong. But I was chatting with a couple of club members who both have Tikkas in .223 and both of them said they struggled to get good accuracy initially and seating depth made all the difference for them.

It's not directly relevant, but my Tikka in 6.5 CM has done good groups with everything I've put through it and I haven't bothered with messing around with seating depth.

 

[sauer]

Every rifle is different
Some will just group whatever you throw at it in a acceptable minute of deer fashion

Others will struggle then wham! Find sweet spot but takes an effort getting there

Try finding powder charge that works best for you first, once found that then try seating depths

Paul

 

[Mungo]

I worry that you're right, and there's something wrong. But I was chatting with a couple of club members who both have Tikkas in .223 and both of them said they struggled to get good accuracy initially and seating depth made all the difference for them.

It's not directly relevant, but my Tikka in 6.5 CM has done good groups with everything I've put through it and I haven't bothered with messing around with seating depth.

I’m always very suspicious of claims that seating depth makes a big difference.

There are so many far more influential variables. And the sample size required to actually determine that seating depth is the relevant one is far larger than most club shooters ever shoot.

 

[DVS1]

When I began the reloading journey I was under the assumption that powder charge nodes were more prevalent to group size and seating depth was an ability to fine tune.

I saw this and in testing and seating depth gained me maybe .2 or .3 of an inch.

My load with me doing my part is around the .3 to .4 in range conditions. I didnt bother go chasing any further as Mr Fox won't know. 3 from .6

 

[Utectok]

I personally used to be a bullet length matters tune the rifle guy but the more I experience it and read about it the more I’m of the opinion if it does matter it’s almost undetectable. Now I leave lead bullets at Sammi spec and copper I jump 120thou roughly not that I’ve even measured my lands on my last two barrels.

 

[longtail22]

I got a case, and a bullet, put a small amount of thread lock inside the neck of the case. Put the bullet in the case and then put the bullet& case in the rifle. Closed the bolt, left for 10 min, opened the bolt, out came the case with the bullet stuck in it.. then measured the head to ogive, then backed off a few thousandths .,