Measuring lands in Tikka 22-250

[Diddums]

I might have missed what projectile you are using but I load for a Tikka T3 SV in 22/250. It shoots 55 grain Vmax in the low .2s at 100 and 1.2 at 300. I load them 2.480. It should get you in the ballpark if you use Vmax.

I've been using Hornady Z-Max, Sierra Blitz Kings and now trying to work up a load for Sierra SBT Game Kings. I have only loaded all these to just below 60mm COAL which is about 3mm shorter than your load.
The best group i have managed is .5in @ 100m for a 5 shot group, ill be interested to see how i go when i measure it up properly.

[Diddums]

I received my COAL gauge and bullet comparator kit today so I'm going to measure it all up tonight.

[Member-Deleted]

Diddums mate have you blued the backs of the locking lugs to see if they both are touching the same amount and at the same time when
the bolt is closed
some times it is possible for one to touch harder than the other and probably feel like a little resistance with a shell inserted into the chamber
and the bolt being closed
Just and after thought as I had a remmy with that problem quiet a few years back the gunsmith fixed it by putting grinding paste behind the one
hitting the hardest till it moved back then he lapped them both but after doing that you test the head space again although it should be good as
paste doesn't remove much metal
Just a thought mate

[Diddums]

Diddums mate have you blued the backs of the locking lugs to see if they both are touching the same amount and at the same time when
the bolt is closed
some times it is possible for one to touch harder than the other and probably feel like a little resistance with a shell inserted into the chamber
and the bolt being closed
Just and after thought as I had a remmy with that problem quiet a few years back the gunsmith fixed it by putting grinding paste behind the one
hitting the hardest till it moved back then he lapped them both but after doing that you test the head space again although it should be good as
paste doesn't remove much metal
Just a thought mate

No I haven't tried that but I'll give it a go.
No harm in checking.

[Diddums]

So I measured my chambers COAL tonight and it was 2.134", which is quite crazy considering that i had been loading my rounds .106" (2.7mm) shorter than my COAL.
I'm looking forward to seeing how they go.

I also measured my headspace and I tried to bump it back about .004 but I was having a hard time getting it consistent.
Is it normal to have variances in headspace measurements by +/- .001

Also should I be concerned it the projectile is only seated about .196 - .236 (5-6mm) in the neck?
They didn't feel loose or anything.

I did have one casualty though.

Resized_20180510_210353_5987.jpeg (84.95 KiB) Viewed 3710 times

[Stix]

I assume when you mean your chambers coal you mean the measurement to the ogive when the bullet is touching the lands...?
Keep in mind this measurement will be different for every type & even often each different batch of bullets.

Im not sure what others do, but i only bump the shoulder back enough so it chambers without resistance-or ideally when i can just feel it as per marksman's suggestion when finding the lands (feeling for same but with shoulder of case, not projectile)--so .001"-.0015" shorter is plenty...i think .004" is too much bump--your just working the brass unnecessarily & risking different results from load testing due to smaller case capacity with such a large bump.

Just check cases in the chamber as you wind the die down & lock the die when the cases are just chambering ok as per above--i like to try a few cases each time you change the die just to be sure.

Headspace/case shoulder measurement variations--do you mean variations from sizing a case, or measuring a once fired case...?

Either way i easily get variations of .001" & believe its ok.
however id suggest only neck sizing once they are formed to the chamber.
Once formed to the chamber i still sometimes get variances of .001", but i have sometimes found new cases take a couple of firings to fully form. (Or more to the point they probably spring back less after a couple of firings).

I think 5-6mm of the bullet seated in the case is fine mate-thats basically calibre depth, & ive seated them less than that.

That is a cracker of a casualty...ive had the odd dent in the shoulder from too much lube build up, & a split neck from lack of lube, but that ones a wee ripper...id frame it & give it pride of place on the top shelf of the loading bench...!!!

[Diddums]

I assume when you mean your chambers coal you mean the measurement to the ogive when the bullet is touching the lands...?
Keep in mind this measurement will be different for every type & even often each different batch of bullets.
yes, I measured it with a bullet comparator kit. I did measure about 10 projectiles from the ogive and there was a bit of variation by a couple of thou.

Im not sure what others do, but i only bump the shoulder back enough so it chambers without resistance-or ideally when i can just feel it as per marksman's suggestion when finding the lands (feeling for same but with shoulder of case, not projectile)--so .001"-.0015" shorter is plenty...i think .004" is too much bump--your just working the brass unnecessarily & risking different results from load testing due to smaller case capacity with such a large bump.

Just check cases in the chamber as you wind the die down & lock the die when the cases are just chambering ok as per above--i like to try a few cases each time you change the die just to be sure.

Headspace/case shoulder measurement variations--do you mean variations from sizing a case, or measuring a once fired case...?
I mean that when I'm sizing the cases they were all coming out of the press exactly the same length, there was a bit of variation.

Either way i easily get variations of .001" & believe its ok.
however id suggest only neck sizing once they are formed to the chamber.
Once formed to the chamber i still sometimes get variances of .001", but i have sometimes found new cases take a couple of firings to fully form. (Or more to the point they probably spring back less after a couple of firings).

I think 5-6mm of the bullet seated in the case is fine mate-thats basically calibre depth, & ive seated them less than that.
I wasnt sure as they are a lot longer than the max cartridge length in a reloading book

That is a cracker of a casualty...ive had the odd dent in the shoulder from too much lube build up, & a split neck from lack of lube, but that ones a wee ripper...id frame it & give it pride of place on the top shelf of the loading bench...!!!
I pushed on the press a little too much and that was the end result.

[sungazer]

Yes that is am issue with Hornady seating dies. a lot of seating dies you can adjust so the shell holder touches the die but not one of these. You have the seating die wound down to far it needs to be wound out a few turns. It is also a die that will put a crimp on if in too far which you dont really want either. I assume you re read the instructions and worked it out?

[Stix]

Not sure if this will help diddums...
But one thing i do for consistant measuring, when fitting the hornady measuring equipment to calipers...

I leave the grub screws loose until everything is pushed up together/calipers are closed.
With thumb pressure still on closed calipers i then do up the grub screws & zero. It just helps to ensure no movement can happen.

You get to know certain measurements for certain rifles & bullet batches in your head & soon know if the comparitor bits aren't in the right spot on the calipers.