How far off the lands?

[big ears]

Hi sorry probably done to death.

I am loading 223 55gr vmax and am using 22.2 gr Ram**** xterminator. The load is right in the middle of the load data and shoots 1inch groups at present.

i load 20 thou off lands and wondered about trying to alter this and see if I can tighten the group. Should I set up a ladder starting 5 thou off the lands to say 30thou off and see what happens to the group?

As the load data is in the middle of the range am I less likely to have pressure signs as I get closer to lands?

thanks for your help

​BE

 

[Muir]

Hi sorry probably done to death.

I am loading 223 55gr vmax and am using 22.2 gr Ram**** xterminator. The load is right in the middle of the load data and shoots 1inch groups at present.

i load 20 thou off lands and wondered about trying to alter this and see if I can tighten the group. Should I set up a ladder starting 5 thou off the lands to say 30thou off and see what happens to the group?

As the load data is in the middle of the range am I less likely to have pressure signs as I get closer to lands?

thanks for your help

​BE

Pressure? Not that you'd notice. Seating depth can effect accuracy. I prefer to seat as deep as I can.
Really interesting choice of powder. How does it smell when it burns??~Muir

 

[mereside]

Pressure? Not that you'd notice. Seating depth can effect accuracy. I prefer to seat as deep as I can.
Really interesting choice of powder. How does it smell when it burns??~Muir

 

[Gunner223]

I shoot 55g v max and there set to 5 thou of the lands, with 25.5g of n133 and this gives a 10mm group at 175yds

 

[Sharpie]

i load 20 thou off lands and wondered about trying to alter this and see if I can tighten the group. Should I set up a ladder starting 5 thou off the lands to say 30thou off and see what happens to the group?

First I would try to find the best charge weight for a wide accuracy node before playing with bullet jump.

​Consensus seems to be that charge weight is more important than bullet jump, discussed here lots.

As the load data is in the middle of the range am I less likely to have pressure signs as I get closer to lands?

You've got that the wrong way round. As you move the bullet further from the lands the pressure will likely increase. As you get closer to lands pressure will likely decrease, until you get close to jamming the bullet.

Suggest you start at say 50/1000 from lands, find an accurate charge weight at as high a pressure as you are comfortable with, then try seating seat the bullet closer and closer to the lands. Doing it the other way around is riskier.

 

[cambsman]

Priceless comment from Muir. Almost choked!

 

[big ears]

Really interesting choice of powder. How does it smell when it burns??~Muir

The honest answer is distinctive and slightly amoniacal. But very different to other powders.

​BE

 

[big ears]

First I would try to find the best charge weight for a wide accuracy node before playing with bullet jump.

​

that was how I reached 22.2gr by finding best load. Accept what you say about had depth wrong way round, my mistake.
​

 

[Muir]

The honest answer is distinctive and slightly amoniacal. But very different to other powders.

​BE

~Muir

 

[cambsman]

Not sure he got it Muir!

 

[reggiegun]

The honest answer is distinctive and slightly amoniacal. But very different to other powders.

​BE

​ram****

 

[cambsman]

There you go! Always humour to be had in a typo

 

[Muir]

Not sure he got it Muir!

That alone is worth a smile.~Muir

 

[big ears]

Not sure he got it Muir!

Oh yes he did!

 

[bewsher500]

not one for "x thou off the lands" normally but I started contemplating this while researching a load for my 300wm
now I already know the 300 has a short neck
Most of the US forums advocate small jumps for this bullet to counter the short neck and aid concentricity/stability

I am loading 208gr AMax (for big deer obviously.....joking, before the keyboard nutters come out!)
They a big barstewards.....bullets are 39mm/1.54" long!! It also has a very long narrow profile from tip to Ogive which

I started looking at the dimensions involved (to tip not Ogive)

Max Magazine length: 88.20mm - 3.47" (single feed it is then!)
OAL to touch lands for 208gr AMax: 93.93mm - 3.69" (its a standard Tikka barrel.)
OAL when seated "calibre depth"
on bearing surface: 92.25mm - 3.63"


now from my maths there is no way to seat close to the lands without having a very short grip on the bearing surface of the bullet

that said most of my other rifles don't like long seated rounds, in fact the .222 got exponentially worse the longer the OAL!
hoping this one is the same!

 

[coire257]

Hi, My experience is that it never made a significant difference, but just don't let the bullet touch the lands. Good luck with your experimentation.

 

[Brithunter]

Bewsher,

The blasted short neck on the 300 Win Mag has been it's bug bear since the marketing boys insisted on it. I suppose that I was fortunate with mine as it was a Ruger No1B so no magazine length to worry about. BTW I found that the 200 Grain Speers shot very well and according to Peter Frost of Empire Gunsight Co they worked very well on African Game including Baboon.

Just looked and I was loading the Speer 200 Flat Based bullets to a COL of 3.450". That is overall length measured from head to bullet tip using a vernier caliper. H4350 worked well it seems.

 

[bewsher500]

I have discovered that it is not so much a seating issue as a case volume issue

when you seat a 1.5" long bullet to a OAL of 3.5" in a case of 2.6" long then an awful lot of it is down past the shoulders

if you are trying slower powders (like 75gr of N165 for example) I am just wondering what that does to the pressure potential!!

soon find out
just loaded up 45 rounds in increasing weights for N160, N165 and H4831sc
Seated to 91mm OAL (tip) for happy medium between very short mag length, on the lands and over calibre seating depth

noisy day ahead!