Help Needed with 7mm08 loads

[HuntClub]

I am shooting a Tikka. I have measured the Ogive to the lands for a 120 TTSX and found it to AVG 2.337". When I test the COAL with this Ogive it is 2.90". WAY too long for the magazine. So, If i load to 2.800 my ogive measures 2.215. This is already 0.122" off the lands.

I have found my best grouping with the ogive measure at 2.175" which gives me a COAL of 2.765". I have searched the best i know how but have not found anything that states what the absolute minimum COAL can be.

Has anyone in here tested this before - or found info that gives the minimum coal measurement?

 

[ChrisNZ]

The 120 TTSXs in T3s are known to be able to tolerate a decent jump. I load mine to just under max mag length (1.83") and they shoot great.

If it still concerns you, get one of the long mags and have the bolt stop altered.

 

[Bill Norris]

I am shooting a Tikka. I have measured the Ogive to the lands for a 120 TTSX and found it to AVG 2.337". When I test the COAL with this Ogive it is 2.90". WAY too long for the magazine. So, If i load to 2.800 my ogive measures 2.215. This is already 0.122" off the lands.

I have found my best grouping with the ogive measure at 2.175" which gives me a COAL of 2.765". I have searched the best i know how but have not found anything that states what the absolute minimum COAL can be.

Has anyone in here tested this before - or found info that gives the minimum coal measurement?

I don't believe minimum COAL is published info for any caliber or cartridge.

 

[centerlineseal]

If it still concerns you, get one of the long mags and have the bolt stop altered.

This!

 

[bozo699]

The 120 TTSXs in T3s are known to be able to tolerate a decent jump. I load mine to just under max mag length (1.83") and they shoot great.

If it still concerns you, get one of the long mags and have the bolt stop altered.

^^^^^^^ This!....
I bought a .270 mag and shortened my bolt stop took less than 30 minutes and I can shoot jammed if I want.
Wayne

 

[Straightshooter1]

I am shooting a Tikka. I have measured the Ogive to the lands for a 120 TTSX and found it to AVG 2.337". When I test the COAL with this Ogive it is 2.90". WAY too long for the magazine. So, If i load to 2.800 my ogive measures 2.215. This is already 0.122" off the lands.

I have found my best grouping with the ogive measure at 2.175" which gives me a COAL of 2.765". I have searched the best i know how but have not found anything that states what the absolute minimum COAL can be.

Has anyone in here tested this before - or found info that gives the minimum coal measurement?

If you haven't already read articles like this one regarding bullet jump, you may want to go here and read the 4 articles regarding it.

Then there's Erick Cortina's idea which he has expressed on YouTube.

Last year I decided to not "chase the lands", as Erick puts it, as I've been doing and see what I might learn from my own experience. I had a good load that was working very well at .010 off touching the lands (COAL: 2.860) for my 24" Krieger barreled .308 mounted on my RPR with 43.8 grs IMR 4064 behind 168 SMK's. Now, after 9 months and 1,533 rounds fired, using the same load I'm still seating them to the same seating depth and the lands has moved where the jump is now .064 and for all the time and as it changed I'm still getting bug holes with that same load.

Hmmm??? So, why am I still getting the results good results with that much change in jump? I'm inclined to conclude that it's NOT much to do with the distance the bullet has to go to engage the lands that's important; it's maintaining the same case volume for the powder charge that set up the harmonic for the accuracy node. To maintain that case volume, the seating depth much be the same. In testing the new much longer169 SMKs I decided to seat them to the same depth (where the base of the bullet is just as deep in the case as with the shorter 168 SMKs) so that the case volume was the same though the ojive was back close to .010 off and using the same IMR 4064 power, though a slight different charge . . . but close to the same pressure that generates the harmonic that's giving me bugholes.

So, if your mag is limiting you to how close you can get to the lands, I wouldn't worry about it. Just find a somewhat long load that fits the mag and gives you tight groups and keep it there, as Erick suggest, until you see your groups opening up.

 

[Lefty Trigger]

There is too much in that whole "close to the lands" thing. Seat your bullets at the book length and give them a try, you might be surprised. I found my 6.5x47 Lapua shoots awesome with the bullets jumping .077 which is factory load length.

 

[7887mm08]

There is too much in that whole "close to the lands" thing. Seat your bullets at the book length and give them a try, you might be surprised. I found my 6.5x47 Lapua shoots awesome with the bullets jumping .077 which is factory load length.

I have been shooting a tikka t3 in 7mm08 since they first came out. I was new to reloading and i developed excellant loads using book oal. I still use that load.

 

[Zero333]

I've jumped 30cal 130 TTSX a bit more than 0.200" and they shot awesome.

Load them at 2.800" and go shoot !