Touching the lands

[Elliott]

OK, so I'm trying to develop a good load for some Nosler 40gn ballistic tips using Viht 133 in my 1/12 twist .223 I got a good size pack of the Noslers given FOC so I'd like to develop a decent load for them. First attempt proved disappointing but I'm going to persevere:

http://i863.photobucket.com/albums/ab192/elliott_g/Mobile%20Uploads/DSC_0291_zps7fb23090.jpg

I think I slipped up the first time by seating the Nosler's too deep at 2.250 so tonight I've loaded some at 2.264 to see how they group. I've just run a dummy round through the rifle having marked it up with a sharpie and noticed some rifling marks. I've taken the dummy round back to the press and seated it a bit further back at 2.255. After cycling the round again I've noticed that it's just touching on one side leaving a small 'line' mark in the black sharpie.

Do you think this is sufficiently seated to give enough jump? I don't really want to go back to 2.250 as the last results we not exactly promising.

[MrCetrizine]

You need to get an OAL gauge. You'll be guessing and wasting bullets until you know the exact length to the lands and then you can work from there.

 

You also need a comparator to measure to the ogive as bullets are not at all consistent in length from the ogive to the tip.

[Elliott]

You need to get an OAL gauge. You'll be guessing and wasting bullets until you know the exact length to the lands and then you can work from there.

 

You also need a comparator to measure to the ogive as bullets are not at all consistent in length from the ogive to the tip.

I've got a Sinclair comparator, only arrived recently and I'm pretty new to reloading. Any advice would be appreciated

[mitch308]

Have a look at Spuds vid

 

It tells you all you need to know

[gbal]

Elliot,as advice given. You just have to get a comparator etc if you are serious about seating depth.

Bullets simply are not all the same length-and I Mean from the same box.et alone bearing surfaces-but don't even go there(just see post on some top selling bullets currently.)

So OAL is meaningless-your rifle will have it's preferences,perhaps different a bit from another rifle of the same model. Your measurements are fine compared to your other meaurements with the same tools,but not to someone elses-these comparitor tools are not precision made,so vary a bit- nor is micrometer 'feel' equal between humans,even with the best of micrometers.

22cfs often like a ten thou 'jump',but you may need to vary it a bit...5,10,15,20 etc to find the sweet spot-just as with powder-though the seating depth coneributes less to precision. It may/not prefer Noslers.V133 should be excellent.

Remember too,not all rifles,and especially non custom ones,are actually capable of very fine precision on a consistent basis-that's why custom premium barrels get sold! Good luck.

 

gbal

[MJR]

Comparators are good but you are working from the shoulder of the case - fine if you use a case fired in your chamber but not so accurate if you use a std case as supplied.

 

A cleaning rod with two adjustable collars - a local engineering company will easily turn you two collars and fit a grub screw.

 

Put the bolt in your rifle and slide the cleaning rod into the barrel until it touches the bolt face, slide the collars up to the muzzle and lock in place. Remove the bolt and slide the cleaning rod towards the muzzle 6". Push a bullet into the chamber gently until you just feel it touch the rifling. Hold it in place with a pencil. Gently slide the cleaning rod in until it contacts the bullet tip. Unlock the front collar and slide it forward until it touches the muzzle and lock it in place. Measure the distance between the two collars. This is you overall length from base of case to tip of bullet - with that bullet.

 

Vince aka The Gun Pimp posted this method and i've used it ever since. It's simple and accurate.

[Elliott]

Comparators are good but you are working from the shoulder of the case - fine if you use a case fired in your chamber but not so accurate if you use a std case as supplied.

 

A cleaning rod with two adjustable collars - a local engineering company will easily turn you two collars and fit a grub screw.

 

Put the bolt in your rifle and slide the cleaning rod into the barrel until it touches the bolt face, slide the collars up to the muzzle and lock in place. Remove the bolt and slide the cleaning rod towards the muzzle 6". Push a bullet into the chamber gently until you just feel it touch the rifling. Hold it in place with a pencil. Gently slide the cleaning rod in until it contacts the bullet tip. Unlock the front collar and slide it forward until it touches the muzzle and lock it in place. Measure the distance between the two collars. This is you overall length from base of case to tip of bullet - with that bullet.

 

Vince aka The Gun Pimp posted this method and i've used it ever since. It's simple and accurate.

That's a great idea and funnily enough one I watched on YouTube last night. I think a bit of insulation tape on the cleaning rod would be a good way to measure the distances

[gunner]

Well the way i learned is a bit crude but it works good for me , take a fired case put in the shell holder in the press and raise the case into the air in the press .Now with your FL die start to screw in the die until it contacts the case ! Now lower the case . Now ever so slightly screw the FL die in just at smidgen more so that it "just" starts to size the case mouth . You want just enough tention to hold a bullet but be able to push / pull the bullet with a finger and thumb, seat the bullet by hand at say 2350 then chamber it closing the bolt fully , then carefully extract the case not letting it get spat out as normal - use a finger in the ejection port to stop it ! Voilla , measure the overall and thats touching the lands . Do it several times to get an average . My factory remmy 10 thou off was 2283 but a sierra blitzking , not rocket science but it works

[bewsh]

You don't say if this is your first time working up a load or just a tricky one

Sorry if this seems patronising, its not meant to be but do you not need to find an accuracy node/charge level before you start looking to fine tune with seating depth?

 

Assuming your 1:12 is a factory barrel it is going to be throated for factory ammo of all derivations so quite long.

Seating a short 40gr BT really long will leave you with a very small bearing surface in the neck of the case

Personally I would start with a minimum calibre depth seating or Book OAL to get your charge levels right.

Nosler book data is 2.26" bang on (to the tip)

 

The way I have always worked up:

Once you have found an accuracy node then you can either split the charge level into smaller increments either side and/or tweak OAL

The charge levels on your target are:

23.8gr, 24.0gr, 24.5gr, 24.8 gr

 

0.2, 0.5, and 0.3gr increases from one to the next

Those are big jumps in a little case and could easily skip a node

 

You are also almost 2gr off Vhit book max, their numbers are usually very moderate, given your highest group is probably the best I would push them a bit faster and see what happens

 

I have yet to find a rifle that won't shoot significantly sub MOA with a decent jump, some even prefer it

[Elliott]

Not sure I've found an accuracy 'node' as such just working up a load for the 40gn Nosler's. You've seen the group I've achieved with them so far so I'm looking to improve on that.

 

I've loaded some more up at 24.5gn, 24.8gn and 25gn and set the COAL at 2.260 so I'll see how I get on with these

[gbal]

Bewsh makes a god point-gt your powder load sorted first-2 grains under V's max is probably way too low-work up towards the V max,as you seem to be about to do.Thee is usually a node near the max-which is the one you want.

 

Choose the best groups (preferably more than just 3 shots-two groups of three shots is fine,prob better than one of five-you really need a decent sample-

With that powder load,try seating-you still seem talk in OAL-that won't work reliably-thats why you get a comparator to use ogive -then the jump is the ogive to rifleng distance.Despite the several methods suggested,as you have a comparator,I"d use that-they all have 'subjective' aspects,but adding in several more really doesn't help. ( getting a fired case threaded is a good move,and costs less than a trip to some engineere-Spud on here does it-but you can get close with the supplied case-remember it's all 'comparator'-how one measure stacks up against another-that is not at all the same as getting an absolute correct measure,though you may-you want to know which length (base to ogive) is best for tyour rifle-any error in the measures will be there in all-you want the top ranked seating depth.Spud's guide should make the process clear.

 

On seating,I still don't follow your descriptions -if 2.55 was just touched by rifling,then 2.64 would-as you found- be more in contact...which means no jump (it's 'jammed' into rifling,gently maybe,but isn't jumping through any clear space before the rifling engages.-the rifling engages on bolt closure. 10 thou jump is often about where 22cfs perform,but it varies...and you need about a bullet diameter retention in the case neck(ie 224 ish) not hanging on by a tenth of an inch-and absolutely not if jammed-sooner or later you'll open the bolt and get powder spill into the trigger...so,a balance of seating into the case for bullet grip tension,and then find best 'jump' (seating depth)-these two have to co-vary (of course bullets are not reiably all the same length-hence use the ogive-which is much more consistent than overlall bullet length.

 

But,as you are doing,get the powder sorted first.If you get groups much under .5" at 100,you may not get them to shrink much-rifles simply vary,especially factory rifles,which can't be consistently expected to compete with custom £800 barrels. Whether .5 to .3 is actually worth spending a lot of time etc to check out,depends on just what you want to do. Reducing three shots from .5 to .3 is generally pretty low on the list for practical purposes-though much effort is often put into this pursuit (leaving a 2+ inch wind error difference unimproved.....

 

gbal