Just to answer your question from another post…I'm sure this will be asked.

I have not measured to the rifling and backed the off bullet, measuring gap / jump to the lands… I was only trying to duplicate the cartridge length the shooter on the video was loading to.
I made a dummy round to 2.46″ and  made sure it would cycle in my rifle before I loaded the test loads. It did, so I tried it and started with a .5gr lower charge and worked up to the load on the video of 25.5gr for accuracy.  I had loaded to 25grs before with a shorter cartridge lengths so I knew it was ok to start there.

The bolt however is a heavier / sticky to cycle at 2.46″ so my guess is I'm just barely touching the lands.

FYI – The scope is a big reason for the groups as well, 24X power as definitely helped my paper punching accuracy!  I normally have this scope on my 300WSM but switched it up for 223 load development.

Not sure exactly how consistent T3 chambers are, nor A-Max overall bullet length across lots, but my .223 stainless varmint touches at 2.498″

I have a bit of a problem with seating marks/powder compression/bullet crushing seating at 2.460″ with 25.5gr Varget in Nosler brass, so that might be a consideration as far as the 25+gr loads go depending on your case capacity.

Thanks for the info on the chamber!  I have not measured mine, need to do it at some point.
Good info on the Nosler brass, that was my next test when I load more.
Everything for me over 25gr was a compressed load and you would hear some powder crunching.
I don't have a  problem with seating marks on the bullets with hornady die and hornady brass.
I do tap the case to help the powder settle a bit though.

Do you have a go too load that works for you in your rifle?

Not yet, I've just started developing a load for this rifle myself, so I've been following all this chatter closely!  ;D
That 1000yd  milk jug shot got me real excited about the 75gr A-Max…  My local gun shop consistently has good stock on most of the Hornady lineup too – I recently got some promising results out of the 55gr varmint SPSX (one of the cheaper ones on the shelf), ~3/4MOA at 300m across a 1.9gr charge spread on my ladder, so I'll be refining that and my A-Max load next time I'm out.

I'm using Lee dies, and it leaves a light ring on the bullet where it contacts from 25.2gr and up at 2.460 COAL.  I'll probably do my next set of loads seated a bit further out.

Check your PM…
Just sent you some good load data, works really well in the 3 Tikka's we shoot.

I'm glad someone else is experimenting with this and varifing range test.

I've never used IMR 4166 so very interested in the test.
What powder charges you loading?

Good info…the guy knows his stuff.

I pretty much do the same but I test most of my “long range” loads at 200 because it much easier to spot and interpet accuracy nodes at that distance and better yet, test at 300yrds.  Not everyone has the available locations to shoot at further ranges when testing a load, but it does help and get you to a confirmed load faster by looking at OCW information from you rifle.

BUT, for 100yrd paper punching I almost always go with loads that gives the tightest group, and adjust scope to POI. Don't really play with it much when using a temp stable powder.  I don't do any competition shooting so this is what works for me.  I'm only welling to put so much time into load development…some people are obsessed with tinkering.

I was lucky on this 75gr Amax test…that a predetermined COAL and powder charge put me right at an accuracy node.  I still have to determine the seating depth from the lands but you can clearly see on the target that 25-25.5gr of Varget puts me in an accuracy node that gives only a .25″ – .5″ vertical difference on POI @ “200yrds”…That translates to a pretty stable 25.2gr load out to 1000yrds, even by my rookie standards and knowledge of handloading.

Lol…I won't advise shooting in basement! lol…

Little update…I tried the same loads in Nosler brass this past weekend.
25.5gr shot the best in the Nosler Brass as opposed to 25.2gr shooting the best in Hornady.

I need to pick one brand of brass and then stay with it and do more testing.
I tried running a few rounds over a chronograph while I was at the range but it keep getting covered in freezing rain so no correct readings to report.

I plan on loading 20rds with 25.5gr in Nosler…&…20rds with 25.2gr in Hornady brass and doing 1 more range session to see what shoots best and settle on 1 and load. Then get a custom Kenton turret for my Vortex scope.  We do a lot of Coyote hunting from Feb-April so hoping to have it all worked out in the next few weeks.

Totally worded that bad…

20….meaning QTY…edited above.