Finding the lands

[MrCetrizine]

This may well be old news to most people. I've been using this method for a while now, but a friend was recently struggling with seating depth using a Hornady gauge. I showed him this method and he was way off using 'feel' on the Hornady gauge and has now sorted his load.

So in case anyone else is struggling...

 

[Akeld]

Always done it that way myself

[Popsbengo]

Or you can use the Hornady gauge and save yourself a load of trouble about a thou' here or there.

Why do shooters create such voodoo around simple engineering?

[Andrew]

Or you can ignore the lands and seat to the recommended OAL.~Andrew

[MrCetrizine]

9 hours ago, Popsbengo said:

Or you can use the Hornady gauge and save yourself a load of trouble about a thou' here or there.

Why do shooters create such voodoo around simple engineering?

Except I've found the hornady gauge to be out by up to 2mm depending on which set of instructions you use. This method is engineering, the hornady gauge is art mixed with guessing.

[MrCetrizine]

8 hours ago, Andrew said:

Or you can ignore the lands and seat to the recommended OAL.~Andrew

And get the same results as much cheaper factory ammo.

[Popsbengo]

31 minutes ago, MrCetirizine said:

Except I've found the hornady gauge to be out by up to 2mm depending on which set of instructions you use. This method is engineering, the hornady gauge is art mixed with guessing.

2mm, 80thou;  I'm intrigued!  How can that be? All it's doing is presenting a sliding bullet in a case against a back stop. Where could such a gross error occur - I'm genuinely interested.

I use a dowel down the bore to ease the bullet off the lands, take five measurements, with five new bullets and average the result - often the individual measurements are within 1thou.  If the loaded ammo is measured with the same calibers and gauges it should be exact to a tight tolerance.  Works on 223, 308 and 338 without any problems.

Granted the Hornady modified case could be slightly different to one's own fire formed but that's a measurable constant to be offset.

[MrCetrizine]

I found when I was using one, I could feel the bullet entering the freebore as very slight resistance. I could also feel it hit the lands. Depending on the instructions used which vary greatly from pushing until you feel any resistance to push it firmly until it stops, you can get up to 2mm difference.

Also rifles with differing leade angles present even more variation when using feel.

I stopped using the Hornady tool when I borrowed a bore scope and watched the bullet from the muzzle side and realised at how many points you can feel something without it actually touching anything.

[bradders]

All well and good, but you have to keep doing it as the throat erodes, and the more it erodes....the more you have to do it

But chasing the throat is something never talked about here, perhaps because guns are moved on before they wear out and the next fashionable fad gains albeit temporary popularity

[Popsbengo]

5 minutes ago, bradders said:

All well and good, but you have to keep doing it as the throat erodes, and the more it erodes....the more you have to do it

But chasing the throat is something never talked about here, perhaps because guns are moved on before they wear out and the next fashionable fad gains albeit temporary popularity

I agree, it's something I do regularly however the rate of erosion is pleasingly slow on my 308

[MrCetrizine]

I remeasure every 1000 rounds. It's an arbitrary number that sometimes yields no change but that's what I've decided on.

I'm not one for buying new things just because they're new.

[bradders]

I have a photo somewhere, but for the life of me can’t find it.

When I was seriously shooting Highpower and 80 SMKs and JLKs in my AR, and I was a lot keener then, I used to do all this, and I remember starting with an OAL of around 2.450” and ending up at nearly 2.550” give or take

I was using Redding bushing dies with quite a constriction on the neck, and you could clearly see the base of the bullet half way up the neck, such was the wear 

I took a photo of one of the rounds, but it seems to have long since disappeared 

[Popsbengo]

Bradders

In principle is it a matter of removing the barrel, and machining / reaming the chamber back to spec?

 

[gruntus]

Another question to Bradders in relation to Pops question, I'm presuming you may have been shooting quick strings?

Did you see much evidence of crazing due to heat?  Can that be resolved with setting back/re-reaming?

ATB

G

[Andrew]

4 hours ago, MrCetirizine said:

And get the same results as much cheaper factory ammo.

Or ....you get the same results as expensive Match ammunition. It depends on how you handle the rest of the operation.~Andrew

[bradders]

22 minutes ago, Popsbengo said:

Bradders

In principle is it a matter of removing the barrel, and machining / reaming the chamber back to spec?

 

In theory yes, but it’s never that easy

Many barrel tenons have an undercut at the shoulder, so you would have to go back at least that far, that’s .620” on an AR and around 1” on a Rem for example, some barrels wouldn’t be suitable for this, especially if the swamp starts just after or near the recoil lug area

Furthermore it won’t remove the fire cracking that could be quite substantial and pronounced further down the bore

In short, setting back is a false economy with increasingly diminishing returns

Once a barrel is done, it’s done

 

 

 

[bradders]

17 minutes ago, gruntus said:

Another question to Bradders in relation to Pops question, I'm presuming you may have been shooting quick strings?

Did you see much evidence of crazing due to heat?  Can that be resolved with setting back/re-reaming?

ATB

G

I’ve never compared a rapid fire barrel to a slow fire one, so can’t say, I’m not a great believer in borescopes 

Setting back will only take care of the most extreme erosion in the throat, but there will be erosion everywhere, so you’re not getting a new barrel, just one where the wear will be accelerated

Plus with the costs of gunplumbing/labour charges and proof, the actual cost of a blank at a couple of hundred quid is quite negligible

Barrels are consumables, treat them as such

[Brillo]

Bradders last sentence says it all really. In F Class terms (FTR) the bullet alone sets you back 60p per round. The average cost of barrel life is 30p per shot, maybe less if you don’t push bullets at insane MVs.

Now factor in travelling costs, range fees and occasional accommodation, and you soon realise that the barrel is the cheapest component in this sport.

[Popsbengo]

Cheers Bradders, makes perfect sense to me to replace rather than refurbish.

For interest I've just, since posting earlier,  done 5 measurements each bullet type with my Hornady set up:  SMK 155, Lap Scenar 155 and Hornady 178 ELD-M.  in my .308 ORSIS 24".

With all three bullet profiles I got +/- 1thou. each reading with the SMK and ELD;  Lapua cock on (better than 0.5').  I like the Hornady gauge, it works for me.

With regard to erosion (Ignoring the ELD's because I've only recently started developing them)  in 2,109 shots from new the throat has moved back 2thou. for the SMK and 6thou. for the Scenars.  Not much to be concerned with I reckon.

[onehole]

Agree the above video shows mechanical proof but I think as long as your consistent with feel and measurement you can do ok with a Hornady set up and a fired in your rifle modified case is very important. I use my own homemade all metal "Hornady type" tool and with modified cases and check touch points every couple hundred rounds appx and always when starting a new "batch" of same bullets.

[Big Al]

6 hours ago, MrCetirizine said:

I found when I was using one, I could feel the bullet entering the freebore as very slight resistance. I could also feel it hit the lands. Depending on the instructions used which vary greatly from pushing until you feel any resistance to push it firmly until it stops, you can get up to 2mm difference.

Try inserting your case/tool with the bullet hanging far out of the neck, dont think about the bullet just concentrate on inserting the case into the chamber and once it fully home bring the depth stop up gently until you feel it touch the bottom of the bullet.

Ive found that to be the most consistent way of using these tools.

As for the video, its a good way to do it as well.

[Chanonry]

5 hours ago, bradders said:

Barrels are consumables, treat them as such

...and stop bloody worrying about it. Shoot the thing until the pips squeak, enjoy yourself

[No i deer]

Always best done on a clean throat, ive noticed some bullets seemed to measure better more consistently,it's does take some practice to get the feel to master the technique