Tikka T3x tac a1 troubles

[SamBrinkman1]

I have a Tikka T3X Tac A1 in .308 I’ve just started reloading but have pretty good equipment. After a lot of research I decided to do a OCW test with Berger 168 vld hunting. Built up about 20 5 shot groups at different charges all .020 off jam and found what I thought to be a good 1/4 inch group. I then replicated the load to run under a new Labradar recently bought after shooting the initial groups to find sd’s around 25 and an ES of 50 (not good enough to my knowledge). After looking at the bullet and how far it was seated out I chalked up bad velocity’s to not enough surface area contact on the neck of the brass. I switched to Berger 175 vld hunting to get more surface area. I then decided to do a ladder test to try and reach pressure. I never did despite a full case of reloader 15 but found a good velocity node and stuck with it. Then I tested seating depths the way the Berger site recommended and got a 3-shot group all through one hole but when trying to recreate the load I shot it again and it shot about 3/4 of an inch with terrible sd’s and a bad ES of over 50. What’s going wrong?
-reloader 15 powder
-lapua cases
-cci br-2 primers
-Berger bullets

 

[918v]

Assuming your rifle/scope are mechanically sound...

Did you do any fine tuning at all or just the rough stuff recommended by Berger? Berger’s suggestions will get you into the ball park but then you have to fine tune using small increments like .1gr on the powder and .002” or so on the seating depth. I map out my nodes, powder charge vs seating depth to see exactly where they begin and end. Your story tells me you are at the edge of a node. If you map it out you will know where the middle is and then your load will be more stable from day to day.

 

[ShtrRdy]

What size steps were you taking when you did the different powder charge weight tests?

As 918v suggested, it's better to take small steps to look for the sweet spots. I don't use quite as small of steps. For the .308 I would step the powder charge weight in 0.3 grain steps. For seating depth test I like to start with 0.010" steps.

If you can find some Varget give that a try. I seem to end up with Varget for my .308 after trying IMR-4064 and RE-15.

 

[rustyinbend]

Just curious ... you guys are measuring "Seating Depth" using a comparator and measuring "Base" to "Ogive" ... right? I'm sorry if this is a stupid question, but someone had to be secure enough in their masculinity to ask it out loud.

 

[ShtrRdy]

Just curious ... you guys are measuring "Seating Depth" using a comparator and measuring "Base" to "Ogive" ... right? I'm sorry if this is a stupid question, but someone had to be secure enough in their masculinity to ask it out loud.

Yes, that's correct. I don't mind questions.

 

[918v]

Just curious ... you guys are measuring "Seating Depth" using a comparator and measuring "Base" to "Ogive" ... right? I'm sorry if this is a stupid question, but someone had to be secure enough in their masculinity to ask it out loud.

I use the micrometer on my seater die to make depth adjustments.

 

[SamBrinkman1]

Assuming your rifle/scope are mechanically sound...

Did you do any fine tuning at all or just the rough stuff recommended by Berger? Berger’s suggestions will get you into the ball park but then you have to fine tune using small increments like .1gr on the powder and .002” or so on the seating depth. I map out my nodes, powder charge vs seating depth to see exactly where they begin and end. Your story tells me you are at the edge of a node. If you map it out you will know where the middle is and then your load will be more stable from day to day.

Yup I started by doing the big jumps and found it liked .040 off jam so then I fine tuned up and down by .002 and never saw a node but just saw one group that was substantially better then the rest. The ladder test was in increments of .2gr and was also mapped out on a graph.

 

[SamBrinkman1]

What size steps were you taking when you did the different powder charge weight tests?

As 918v suggested, it's better to take small steps to look for the sweet spots. I don't use quite as small of steps. For the .308 I would step the powder charge weight in 0.3 grain steps. For seating depth test I like to start with 0.010" steps.

If you can find some Varget give that a try. I seem to end up with Varget for my .308 after trying IMR-4064 and RE-15.

This was my ladder test graph. I’ve tested a lot of different seating depths probably 50-60 different lengths.

 

[918v]

You’re loading 47 grains of RE15 in Lapua cases under 175’s???

 

[SamBrinkman1]

You’re loading 47 grains of RE15 in Lapua cases under 175’s???

They are seated out pretty far but yes I am.

 

[918v]

U crazy.

 

[SamBrinkman1]

U crazy.

What’s crazy about it? I never saw pressure signs and it fits in the case.

 

[ShtrRdy]

From the velocity test I would try some different charge weights around 45.8gr. (i.e. 45.5, 45.8, 46.1)
..... did you skip some charge weights on purpose?

Would you mind posting the results of seating depth testing?

 

[SamBrinkman1]

From the velocity test I would try some different charge weights around 45.8gr. (i.e. 45.5, 45.8, 46.1)
..... did you skip some charge weights on purpose?

Would you mind posting the results of seating depth testing?

I did 2 different ladder tests this was the only one that had a node. Here’s a pic of the seat depth test shots. I found that according to Berger I should do big jumps then fine tune after. this is the fine tuning. The top left group was what I thought to be the backside of a node and I shot some depths in front of it on another occasion but they were all over 3/4 inch.

 

[918v]

What’s crazy about it? I never saw pressure signs and it fits in the case.

Because 44.5 grains is max under a 175SMK loaded to 2.800”. The 175SMK is a much shorter bullet. So even tho you’re running a long coal, it doesn’t justify a 2.5 grain powder increase because your bullet is longer by .100”.

 

[SamBrinkman1]

Because 44.5 grains is max under a 175SMK loaded to 2.800”. The 175SMK is a much shorter bullet. So even tho you’re running a long coal, it doesn’t justify a 2.5 grain powder increase because your bullet is longer by .100”.

It’s a Berger vld it lets me seat them a lot further out in the case

 

[918v]

Your vld is a longer bullet than the smk. You seating them out farther is negated by the fact they are longer. 2.5 grains over max is insane.