Thread: Sierras new Game changer bullets

An update on some recent discussion with Sierra about the 90gr 6mm GameChanger. I have a good friend in the UK who has just spent a small fortune trying to get these to work in his Tikka, and he asked for some help. I'd been in touch with Sierra before, so I asked some questions...

On the Sierra blog (https://sierrabulletsblog.com/2018/0...-gamechangers/) a reader asked the question we all want to know the answer to:



I calculated stability for the typical 1:10" .243 barrel using the JBM calculator, using a value of 0.14" for the plastic tip length. It returned a Miller value of 1.276, which is just below the stability threshold of 1.3. MilSpec stability is 1.5, and a stability value between 1.3 - 1.5 is classed as "marginal" as per the Litz / Berger definition. So my conclusion was that Sierra was flirting with poor accuracy in a wide range of factory .243s with 1:10" twist barrels.

In the US market, the .243 Winchester rifle market is dominated by Remington (1:9⅛") and Savage (1:9¼"). Surprise surprise, these barrels achieve a Miller value of 1.5 with the 90gr GameChanger.

So to my mind, the statement in the Sierra blog by Duane Siercks was misleading. Well, you could suggest its plain wrong.

So I asked his colleague Philip Mahin about this. Mr Mahin said "I have heard both sides of the fence with our new 90gr TGK in a 1-10” twist, some say it works great and others can’t get accuracy because of borderline stability. I do know that a 1-9” twist will stabilize it just fine so it may need to be used in a different firearm [to the 1:10"]".

Eh?

I then took a look at the new Sierra load data app. Sierra has changed something quite fundamental on their .243 Winchester page.



Gone is the 1:9⅛ Remington test rifle, replaced by a "universal" 1:8" barrel. I pointed out to the Sierra tech that it is not possible to buy a factory .243 rifle with a 1:8" barrel (their may be one specialist option, but no standard "off the shelf" options from the normal manufacturers.



I didn't hear back.

To my mind Sierra is fudging the numbers and presenting a bullet to market that has a high chance of not working in a large number of factory rifles.

It is also worth pointing out that in the past, Sierra has clearly communicated twist requirements on their website, and packaging. There's no mention of required twist rate for the 90gr GameChanger.

Why would they do this?

It will be very very interesting to see (next month) what the Hornady ELD-X 90gr is like in the .243 Win 1:10", as the bullet is slightly shorter, and has a Miller value of... 1.5. Ha!

I've posted this to help get the message out that if you spend $92 on a box of 6mm GameChangers for your 1:10" twist .243 Win, you may well find that they don't work. If you want to try them, I strongly suggest you buy a sample pack first.