Setting up bullet jam length - confused

[Cruzer Dood]

Hey Guys, I've been watching Eric Cortina on u-tube, and recently he did a piece explaining how seating depth didn't matter, as long as you knew bullet jam and seated acordingly. He went on to doing a ladder test for best load. I'm working with a Rugar M77/22H that has been K'd by Randy at CPC, and a CZ527 in 221FB. In the past I would put a flat base bullet in an empty case, with bullet reversed and chamber. This would give me a dummy round that I could measure from base to lands, using a Hornaday comparator set. After watching Eric, I broke out my Sinclair seating depth guage, followed the directions, and came up with totally different readings. On the 22KH, I get 1.475 using reversed bullet method vs 1.706 with the Sinclair tool. Fire Ball is simular, 1.510 w/rb vs 1.875 w/tool. I'm not sure at this point what I'm doing wrong, or is it just the difference between the two methods. Like they say, " you don't know what you don't know ", and at this point thats where I am. Sorry if this is long winded but just wanted to get the facts to you. Many thanks for any help, Al

[SmokinJoe]

Why are you putting the bullet in backwards? I think the system is designed to have the bullet in normal orientation so as to mimic a loaded round. If I understand what you said you have done it both ways with quite different results. I think you will get where you want by using the bullet forward (as in like it would be seated). Do you have the correct modified cases for the Hornady/ Stoney Point system? And the bushings? This sort of set: https://www.midwayusa.com/product/101273351?pid=231904
And this tool: https://www.midwayusa.com/product/1012747079?pid=570611
Plus modified cases for each round
And this adapter for the Hornet: https://www.midwayusa.com/product/1012753414?pid=654262
If you use these tools correctly you will get good seating depth information.
Hope this helps.

[Cruzer Dood]

SmokenJoe, the reversed bullet method idea I got from reading John Barness of Rifle/Handloader for years. Its a method I first started with. As I got more into the loading aspect and gained a little more knowalage, I bought some tools for specific steps of the process. Yes, I do have the comparator set you show in first example, along with the headspace ones as well. No, I'm not using the other two. I am using the Sinclair seating depth tool, which is a steel rod, with 2 stops that you lock in position, in a guide that fits in rear of action. Reversed method has worked for years, is simple, but how accurate? Sinclair tool is probley more accurate way to measure, just seemed results would of been closer. Thx for reply.

[Cruzer Dood]

Just to clairify, using Sinclair tool bullet is incerted into chamber NOSE first. Using reversed method bullet is put in case backwards, chambered, using rifling to push bullet into case, giving you a base to lands measurement ( in theroy ). You probly knew the last one, but I was trying to be clear. Thx , Al

[TinMan]

Are you hitting the base into the chamber end maybe, rather than the tapered lands? If there is that much difference length, maybe the base is too sharp to actually hit the lands.

[Rocklong]

In all reality it doesn’t really matter what length you come up with. Put the bullet in the right way wax it up and close the bolt on it. Then back it off 20-30 thousandths and test seating depth back from there. As long as you don’t have pressure signs or problems keep shooting. Good luck!!!!