Great information! Love the precision and factual accuracy of investigating the ballistics.
A friend of mine just completed some testing and found a variance of up to .020 in base to ogive on these bullets. They usually were .004, .006, or .020 all in the same box like they were made on different machines and thrown in the same box. This was consistent across 5 boxes of the same lot.
The very reason I quit using Sierra bullets years ago. How hard can it be to keep them in the same box?
Regards, Paul
www.boltfluting.com
Pretty awsome response from Sierra, question on the 168gr TMK 30cal.
Will it stabilize in a 13 twist barrel?
Has the boatail been re-designed to stabilize thru transonic barrier crossing?
Also any tuning advice for the 168gr TMk, i have read some people had trouble and some dont. Any particular way to test them?
Eric32 - yes, the 30 168 TMK will be just fine out of a 13 twist barrel.
The 30 168 SMk has a 150 thou 13 degree boat tail and the 30 168 TMK has a 180 thou long 9 degree boat tail. While this was not done specifically to help it stabilize thru the transonic barrier (it was done to reduce drag) it will help with that by default.
Due to the secant design of the TMK, they will be a little more finicky to load tuning for sure, but many are making slight changes to their current loads and having good success. First thing to try would be bullet jump as this bullet will be less tolerant to jump changes compared to the SMK equivalent.
If you have any issues - our tech line can help from 8am to 8pm central time 800-223-8799 or sierra@sierrabullets.com
Thank you,
Matt
I can personally say the 168gr TMK are great and my 700 sps Tactical 1/12 twist loves them. One ragged hole measuring .207 behind 47.3 GR of 2000MR. At 300 yards just a tad over one inch as well. At 2650fps I had 1.2Mil drop.
What is your zero ?
I ran the numbers but i got 2800 fps to correlate with your 1.2 mil drop for a 100 yard zero
I have worked for Sierra Bullets for 11 years and we have never and will never mix a lot. I also have been through most match bullets makers facilities and I don't know a single one that would ever do that unless it was a custom bullet (not for retail sales) and done at the customer's request. Sometimes an ammo manufacture that buys millions of bullets does not want to deal with all our small lots and will request that we mix lots in drums to make their manufacturing easier. We then make them agree to that in writing before we begin. That is a very rare thing for us and I can only recall a few projects where that was requested. I don't ever recall one for match projectiles.
We run and store bullets into a 16 gallon barrel (if you have ever toured our facility, you will have seen them all over) and a single lot is never larger than what fits into the drum. If the drum only has 2,000 bullets in it - that is all that lot size is. That is why a 100,000 bullet lot is pretty rare for us. Even if nothing changes at all, if the barrel is full and changed out - a new lot number is started no matter what. Our system will not even allow anyone to print the same lot number for 2 separate barrels.
If the person with the TMK's that say they are measuring 20 thou base to ogive would contact us and send in a sample, we would replace them immediately if they truly do measure that. That is unacceptable and would be the largest B2O measurements I personally have ever heard of these measuring by a large margin. We always like to have customers contact us if they have an issue and #1 give us the opportunity to make it right and #2 track down the issue to make sure it does not happen again. Bullets are expensive and you should get what you pay for.
We make millions of bullets per week and I am not here to say we are perfect and never make a mistake. I will say that I will be shocked if they are 20 thou B2O out of the same box, but if they are we will replace them no questions asked. We would replace them if they were 1/2 that.
jsthntn247 - if you would have your friend contact us, we would certainly like to talk to him about being able to check them out and make it right for him if they truly are that far out. He can call 800-223-8799 or email us at sierra@sierrabullets.com
Thank you,
Matt
Yes it's In the new book along with ALOT of other bullets.Anyone know if a litz BC is out for the 168gr TMK?