I made it out to the range Wednesday to do some serious load development work with the 6mmx222. I acquired 200 rounds of new Sako 222 brass with the intention of using them to carefully work up some loads using a good micrometer and reading case head expansion. I finally had some time to do that with four powders and one bullet.

I referenced Hodgdon's manual for it's data, Sam Fadala's article from Handloader's Digest and Quickloads (QL). I have discovered some anomalies. First of all Sam Fadala states he used up to 28 grains of BL-C2 in his 6mmx222. I don't know how he did it. The most I can get in a case is 27 and that's level with the case mouth. I've tried five different brands of brass and they are all within one tenth of a grain of each other for BL-C2 capacity. The most I feel comfortable using is 25 grains and that's fairly well compressed with an 80 grain flat based bullet.

The second anomaly is with QL and Hodgdon's manual. Their data reflects much higher velocity than I am seeing. Take H335 for example. I tried 20-23 grains with a Speer 1211 80 grain spitzer. Quickloads indicates 20 grains should run 44049 psi for pressure and 2558 for velocity. Actual velocity was 2206. On the top end at 23 grains QL shows 68627 psi and 2895 fps. Actual velocity was 2573. None of the cases showed any case head expansion. I was certain the 23 grain load would exceed my expansion limit of 1 and a half thousandths but it showed none.

I kept all of my test loads separated and marked to maintain accurate records of each case. Each case had a before and after reading.

The only powder that showed any expansion was IMR 4198 and that was only at the top charge of 19 grains. Quickloads showed that load producing 63862 psi 2747 fps. Actual velocity was 2518. The rest of the 4198 loads showed no expansion at all.

I tried BL-C2 and Alliant 10X with the same results. Velocity ran 300+ fps behind what QL predicted and no case head expansion.

Accuracy wise, H335 and BL-C2 were the star performers. IMR 4198 turned in some lousy groups, which was surprising to me considering how well it grouped in every 222 I've owned. Alliant 10X was nothing to write home about either as far as accuracy went.

I've got more work to do yet. I'll take the H335 up a grain at a time till I get 1 and a half thousandths case head expansion and then back down a little.

It's interesting the differences between QL, the Hodgdon manual and what my rifle is actually turning out for velocity. None of these loads exhibited any of the traditional high pressure indicators such as sticky bolt lift/extraction or shiny spots on the base. I know every rifle is a law unto itself but this is some significant differences in predicted versus actual performance.

The Hodgdon website lists a max of 24g of BL-C2 with a 75g bullet, so I would be hesitant to using 25g with an 80g bullet. Since you already found a H335 load with star accuracy, I wouldn't push the pressure envelope with H335. If you want a high velocity cartridge, there are plenty out there faster than the 6x222. But if you want an accurate cartridge with moderate velocity, you have what you want.

I think you will find H335 gives you the best velocity and H322 will give you the best accuracy..

I have found that so in my all time favorite the 6x45..I shoot the 60 gr. Sierra HP with H322 and its my tack driver for rock chucks and coyotes. I shoot the GS Customs 75 gr. HP loaded with H335 at almost 3000 FPS for deer and antelope and even coyotes on windy days in the desert where shots are longish.

duckboat,

My quest is not to make a high velocity round from this little cartridge. I know that it is not that. My intention with this post of my observations was to delve into why there is a 300-500 fps discrepancy between the Hodgdon manual/Quickload predictions and my actual range data.

Also there are a lot of powders that were not available when Sam Fadala was playing with it in the 80's. My hope is to develop some data for some of the existing powders.

A good example of some of the discrepancies is that Quickload says 18 grains of AA2495 should drive a 100 grain bullet at 2301 and in reality it clocks 1801, exactly 500 fps less. That would tell me the load is not developing anywhere near the pressure QL predicts.

Hodgdon's manual suggests that 16.5 grains of 4198 should run 2514 fps. An 80 grain bullet should run a bit faster than that but 17 grains of 4198 come out at 2253 with the 80 grain bullet.

Like I said earlier, I'm not after high velocity but I would like to see the cartridge perform at or near it's potential. I will be fine with 2600-2700 from an 80 grain bullet if that is where it is most comfortable pressure and accuracy wise. And I believe this round is fully capable of this level of performance. I would like to know if I can get there safely with the powders I'm trying.

What is your fire formed H20 case capacity?

The H2O capacity is 27.2 grains.

How is the chamber throated?

The chamber is throated fairly long and that's my fault. I failed to provide that information to Pacnor when I sent it off to them. The magazine only allows for an OAL of 2.260 and the chamber is throated to allow for an OAL of 2.368 with the Speer 80 grain bullet.

Pity on the throating.

Sure your chrono is good?

Yeah,

I was sending off two actions to be barreled and just forgot to tell them how I wanted it throated. It's shoots very accurately though.

The chronograph is good I'm sure. I checked not to long ago with some factory ammo in a couple of guns and it was right on. I am headed back up to the slope for two weeks but will check it again when I get back before I proceed with any more load development.

I'm suspicious the long throat may have some to do with the low velocities but I doubt if it's responsible for 300-500 fps.

Not sure what action your using, but in most cases its pretty easy to lengthen the box to fit a long throat. I did that on my 6x45 Sako L-461 and on a number of Mausers in various calibers??

quote:

I think you will find H335 gives you the best velocity and H322 will give you the best accuracy.

That was my experience with a match rifle shooting 85-grain Sierra HPBT Matchkings.

Mine liked 335 for velocity and accuracy, pretty much tied with BL-C2. It didn't like 322 at all.