Need opinions on early pressure signs

[Mountain_Life]

I need some opinions here. I have a Tikka T3 270 WSM. 16" barrel. Norma brass. CCI 250 primer. 145 ELD-X. Loading to max mag length. I'm getting hard bolt lift and ejector marks at what seems to be moderate powder amounts. 56.5 grains of H4350 and 62 grains of H4831sc. I'm not looking for crazy velocity so I've just been shooting closer to suggested starting loads, but this is the first time I've experienced a gun showing pressure signs so early. Thoughts?

I haven't ever gotten into bore scoping or scrubbing. Possible crud ring? Or maybe this is just what the barrel is?

With 61 grains of h4831sc it shoots great, see a recent 100 yard group below.

 

[Mountain_Life]

Also open to powder suggestions. I'm not interested in buying powder specifically for this gun as there is a rebarrel to 6mm in the future. On hand I have h4831sc, h4350, imr4350, h1000.

 

[49ereric]

Seat the bullet deeper and see if you get the same results.

 

[EdP]

Seat the bullet deeper and see if you get the same results.

The Tikka owners on here could tell you if it is common for Tikka mags to be long enough to accommodate a COAL that jams the bullet into the lands. If so, loading to max mag length you may be jammed into the lands. You should check because if you are, the above suggestion may well solve your problem.

For a point of reference, my Lyman manual doesn't list H4350 or H4831 powders but does list the IMR4350 and IMR4831. Bullet wise, no 145 gr but a 140 BTSP. No 4350 loads are listed for bullet weights over 140gr. The max load for IMR4831 is 61.0 gr. Other sources should be referenced but you may be loading on the hot side given this data. The Lyman manual also says that with the .270WSM "The overall length of many premium bullets may require that they be seated deeper into the case than they would be in a longer action."

 

[Mountain_Life]

The Tikka owners on here could tell you if it is common for Tikka mags to be long enough to accommodate a COAL that jams the bullet into the lands. If so, loading to max mag length you may be jammed into the lands. You should check because if you are, the above suggestion may well solve your problem.

For a point of reference, my Lyman manual doesn't list H4350 or H4831 powders but does list the IMR4350 and IMR4831. Bullet wise, no 145 gr but a 140 BTSP. No 4350 loads are listed for bullet weights over 140gr. The max load for IMR4831 is 61.0 gr. Other sources should be referenced but you may be loading on the hot side given this data. The Lyman manual also says that with the .270WSM "The overall length of many premium bullets may require that they be seated deeper into the case than they would be in a longer action."

I appreciate the responses! I saw the same in my Lyman manual. Also referred to my Hornady app and various Internet forums (taken with a grain of salt). I'll look into seating depth.

 

[Mountain_Life]

Doesn't appear that my initial load was jamming into lands, but I went .040 deeper anyway. Loaded up 57 grains of H4350. First 2 shots had no ejector mark or hard bolt lift, 3rd had a little heavier bolt and a very slight ejector mark. 4th and 5th had heavy ejector marks and very heavy bolt lift.

My previous seating depth was similar, no pressure signs until the barrel heated up.

 

[Lawnboi]

Doesn't appear that my initial load was jamming into lands, but I went .040 deeper anyway. Loaded up 57 grains of H4350. First 2 shots had no ejector mark or hard bolt lift, 3rd had a little heavier bolt and a very slight ejector mark. 4th and 5th had heavy ejector marks and very heavy bolt lift.

My previous seating depth was similar, no pressure signs until the barrel heated up.

Are you shooting outdoors with a suppressor now by chance?

 

[Mountain_Life]

Shooting inside with the window open. Suppressor is just a bit outside the window but everything else is inside and warm. Thoughts?

 

[Lawnboi]

Shooting inside with the window open. Suppressor is just a bit outside the window but everything else is inside and warm. Thoughts?

Sometimes cold air down a warm or hot bore, combined with some excess gas seems to cause the case not to stick to the chamber walls quite like it should. No idea if that’s your problem but I try not to develop loads when conditions are prone to causing that. I normally don’t load top end to begin with but I’ll see it when conditions are stacked in favor condensation.

Maybe not what’s going on but I have had some head scratchers especially with warm rifles and headwinds, shooting suppressed in shoulder season and winter.

I like to use a chamber fan in these situations.

One easy way to rule this out would be to shoot the same string without the suppressor.