175 SMK vs TMK pressure

MartyK2500

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I am posting as i am half worried about my starting load, looking for opinions only, in the end I’ll have to make the adult decision.

Been shooting SMKs for 1.5 years now.
In my IBI barrel, i touch the lands at 2.800’’ COAL avg, so i load to 2.780’’,
And with 42.7gn of varget i avg 2705 fps, which is decent.

Wanted to try 175 TMKs to take advantage of that higher BC.
First observation is how Ogive is more in the rear than SMKs, and bullet lenght is longer from ogive to rear than SMK.

I am touching lands at 2.840’’ COAL with 175 TMKs.
So i loaded them to 2.820’’, seems to have lot’s of bullet seated inside the neck.

My starting load is 42.4gn of Varget, which i am hesitant to try.
I was thinking shoot only one over the Labradar and if over 2700 fps take the gun off the line and pull that ammo.
And for the record, i got my SMKs past the 44.5gn/2780fps territory without pressure signs,
I kept my load low all this time as i took advantage of a soft shooting load going 2700 fps.

Especially those who have tried going from 175 SMK to TMK, i am very interested to learn about your experience.

Edit : just figured that i will load 1x at 41.5, 1x at 41.8, and 1x at 42.1
To at least chrony each one and look for pressure going up.
 
Nothing to worry about .020 thou off lands is no prob does not matter changing bullett, you were .020 off lands with your original load , same grain bullet does not matter f different shape.
You will just have to work up load to see if your barrel will like TMK bullet:)
 
yup you're on da right path! See if your rifle likes it. I had to redevelop the load when i switched, ended up at 42.2, 2.84 also.
 
Thanks for confirming,
These we’re todays loads, TMKs are slower and softer in my barrel afterall,
No pressure signs at all, and kept more detailled data once velocity was higher.

Accuracy i will have to test again,
And they are not as accurate as my SMKs... so far, have not done thorough testing yet.

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