6.5x55 Swed Seating Depth

[SixFive]

My custom 6.5x55 is shooting 1/2 MOA with 47.5gr of Staball 6.5 and the 120gr Nos Ballistic Tip (Rem Mag primer). I have the bullets seated at an over all case length of 3.00 as per the Hogdon loading app. I worked a ladder from 44.5gr to 48gr and 47.5 was the best.

At the 3.000 OAL I am .140 off the lands, that is a bit of a jump!

My thought is to load 5 rounds each -
(It is 3.140 COL to the lands with the 120gr Nosler BT bullet.)

.050 off the lands COL- 3.090
.040 off the lands COL - 3.100
.030 off the lands COL- 3.110

The magazine will hold and feed all those lengths so no issue.

NOTE: Yes I know I am outside book on the 47.5gr but this is a modern action that has zero signs of pressure even up to 49gr.

So what do you all think? Am I barking up the right tree to tighten up this group? Thanks!

 

[Flycaster1977]

I think you are certainly in the right frame of mind. Length or lack thereof can have a great affect on your accuracy. Barnes even basically recommends finding your lands and then backing off a little at a time until you find the accurate spot.

However, saami calls max length on these at 3.150, so it looks like you have a lot of room for adjustment.

Dont worry about those hotter loads. I have one swede here that i can push real hard and another that shows pressure signs at max book loads. Both were made in the last 5 years.

I would watch the new lengths for any signs of pressure as you are already at the “edge”.

 

[joshb]

I would take a different approach. I find my “touching the lands” length and test powder loads. Then I back off the lands, little by little and see if I get better groups. Letting bullets jump reduces pressure. Touching or jamming bullets raises pressure.
I agree with flycaster. Book loads for the Swede are usually maxed for the old military actions. Modern actions are stronger. Just watch carefully for pressure signs in YOUR gun.
I have a custom Stiller actioned 6.5x55 and my loads are over book max.

 

[SixFive]

I would take a different approach. I find my “touching the lands” length and test powder loads. Then I back off the lands, little by little and see if I get better groups. Letting bullets jump reduces pressure. Touching or jamming bullets raises pressure.
I agree with flycaster. Book loads for the Swede are usually maxed for the old military actions. Modern actions are stronger. Just watch carefully for pressure signs in YOUR gun.
I have a custom Stiller actioned 6.5x55 and my loads are over book max.

Is it true that at a point seating bullets deeper also increases pressure? When using Quickload seating bullets deeper in the case shows increased pressure. I guess it is a balancing act? To close to the lands, pressure, seated to deep pressure, find the middle ground?

I also read that the 6.5x55 likes .050 off the lands, might be a good starting point, but other forums say the Nosler BT likes .010 off the lands, ugggg. I will go through a pound of powder working these loads Honestly though, this is the fun stuff, I love reloading and having discussions with you guys about it!

I have also noticed case neck tension seems to make a difference, I am settled on .003 for tension, works best on most of my loads.

 

[joshb]

Yup! It’s a balancing act. Years ago, I learned a valuable lesson about it. I had a 308 load that shot fantastic at “touch”. It was a rather warm load, but at that time I thought velocity was King.(I had been spending too much time on Snipers Hide. I was naive.)
Anyway, the loaded round was too long to fit in my mag so I simply took some loaded rounds and pushed the bullet in to “mag length”. 2.96 to 2.8. I happily went to the range to test them. As I remember, the first round locked the bolt. When I beat the bolt back, the primer dropped out on the bench. I went home and did a deep dive search into “pressure signs”. I found this site, with its group of great guys giving advice, and I never left.
Test, test, test…carefully!
A few things affect pressure. Case volume is one of them. Moving a bullet deeper in the case reduces case volume. Different brands of brass will have different internal volumes. That’s why you should retest a good load when switching brands.
Neck tension and crimping can also affect pressure.
Different bullet designs of the same weight.
Different lots of the same powder.
Letting a shell cook in a hot chamber.
Hot weather, cold weather………the list is long.
These days, I’ll work up and find my gun’s max load. I’ll record all the data in my record book. Then I’ll look over my targets and look for a good node below my max load. That way, I’ll have a safety cushion, my brass will last longer and so will my gun.

 

[SixFive]

Is it true that at a point seating bullets deeper also increases pressure? When using Quickload seating bullets deeper in the case shows increased pressure. I guess it is a balancing act? To close to the lands, pressure, seated to deep pressure, find the middle ground?

I also read that the 6.5x55 likes .050 off the lands, might be a good starting point, but other forums say the Nosler BT likes .010 off the lands, ugggg. I will go through a pound of powder working these loads

Yup! It’s a balancing act. Years ago, I learned a valuable lesson about it. I had a 308 load that shot fantastic at “touch”. It was a rather warm load, but at that time I thought velocity was King.(I had been spending too much time on Snipers Hide. I was naive.)
Anyway, the loaded round was too long to fit in my mag so I simply took some loaded rounds and pushed the bullet in to “mag length”. 2.96 to 2.8. I happily went to the range to test them. As I remember, the first round locked the bolt. When I beat the bolt back, the primer dropped out on the bench. I went home and did a deep dive search into “pressure signs”. I found this site, with its group of great guys giving advice, and I never left.
Test, test, test…carefully!
A few things affect pressure. Case volume is one of them. Moving a bullet deeper in the case reduces case volume. Different brands of brass will have different internal volumes. That’s why you should retest a good load when switching brands.
Neck tension and crimping can also affect pressure.
Different bullet designs of the same weight.
Different lots of the same powder.
Letting a shell cook in a hot chamber.
Hot weather, cold weather………the list is long.
These days, I’ll work up and find my gun’s max load. I’ll record all the data in my record book. Then I’ll look over my targets and look for a good node below my max load. That way, I’ll have a safety cushion, my brass will last longer and so will my gun.

Great wisdom you are sharing, THANK YOU!