L461 .20-222 HB project

[Branxhunter]

After a few more discussions with interested friends I loaded up some BM1. By this stage I had also happened to find a nice second hand Zeiss HD5 5-25x50.

These were the groups:







Now if I could just be a little more consistent with my shooting technique I might be able to get rid of those annoying flyers....

Marcus

 

[Branxhunter]

So being pretty happy with the 23.2gn load I put together 20 rounds and checked how it shot at my 200m gong:



and my 250m gong:



Happy with that! Time to head out with the spotlight. After a long three hours I got two in the last 20 minutes - one at around 120m in a patch of thistles:



And the second around 200m away near the top of a hill.

Really happy with how the rifle performed.

Marcus

 

[stonecreek]

Thanks for sharing, Branx!

I've found the .20 calibers to be very accurate little rifles. I own two, which bracket your .20-222 in size: One is a .20 Vartarg (.20-.221 Fireball) and the other is a .20 Tactical (.20-.223 with minor shoulder changes). Both are excellent shooters, but I like the Vartarg better since it burns less powder, heats the barrel less, has less muzzle blast, and kicks out the little 32 grainers about as fast as any practical use requires. Your .20-222 is about as large a case as I think is really useful in the .20 caliber and has all of the capacity needed to boost a 32 grain bullet to its optimal velocity. A somewhat larger .204 Ruger might add 100 to 200 fps or so, but its extra powder capacity puts it well into the area of diminishing returns.

 

[Branxhunter]

The .20-222 seemed like a good way for me to dip my toe into the ocean that is wildcatting, given I already have a heap of brass on hand. Besides, seems like every second varmint shooter has a vartarg these days......

I then got to thinking about finding out what the max load would be for the 32gn z-max in this rifle with BM1. I loaded one of each from 23.8gn (I had previously tested 23.5gn with no issues) up to 24.7gn and fired them watching for pressure signs. Out of interest I used the same point of aim and got this:



So obviously with this powder and projectile this rifle looks like it might be a hand loaders dream with a wide window of powder charges giving a similar POI. The 24.7gn load fills the case to about 2/3 up the neck.

I managed to borrow a chrony, so tried a few charges but mostly only 2 rounds each (only had a few primed cases left). Results were:

23.2gn - 3811, 3808, 3857 fps
24.1gn - 3950, 3968 fps
24.4gn - 4026, 4075 fps
24.7gn - 4116, 4034 fps

Happy with those results! Now I just need to load up a few more and test over a larger number at my chosen load.

Marcus

 

[stonecreek]

Those are great groups. But you might have even better luck with a more precise aiming point than the somewhat uneven black dot made with a marker. Why don't you try printing some free targets with benchrest squares that you can find here: http://www.6mmbr.com/targets.html With the benchrest square it is much easier to bisect the white area inside the heavy black square with your crosshair, giving you a more precise aiming point than trying to center the black crosshair on a black background.

 

[ricksengines]

OK I am extremely impressed. Don't change a thing. The rig looks great just the way it is. Congrats on a really fine effort and bringing a project like this to fruition.

rick

 

[Branxhunter]

I spent a bit more time at the bench today pushing the .20-222 to see what it could do over the Shooting Chrony.

I had loaded one case each using the charges of AR2207 shown below with the 32gn z-max to check for pressure signs, keeping a close eye out for sticky bolt lift, primer flattening and ejector marks on the case head. No adverse signs were noted, and velocities were:

22.0gn- 3948fps
22.3gn - 4063fps
22.6gn - 4104fps
22.9gn - 4158fps
23.2gn - 4263fps.

The resultant five shot group was 0.40".

I also loaded up 25.0gns of BM1 with the 32gn z-max and got 4305, 4359, 4290, 4341, 4304, 4250 and 4290 fps Bolt lift was starting to get slightly sticky at this charge, but primers were fine and no ejector slot marks on the case head.

So it looks like either AR2207 or BM1 will give excellent velocity and accuracy, with BM1 perhaps just edging out AR2207 in the speed stakes.

Marcus

 

[stonecreek]

Sounds like you've got a great little shooter there, Branx.

But beware of depending on sticky bolt lift to warn you of high pressure with small cartridges, for the following reason:

The area of the small .373" .222 case head doesn't transfer nearly as much thrust to the bolt face as the much larger .243/.30-06 head which is .470" in diameter. The .222 case head has an area of .109 square inches, whereas the .243 case head has an area of .173 square inches. This means that the same chamber pressure pushes about 1.6 times as hard on the larger case head, which is why you get sticky bolt lift with the larger case head more quickly than with the smaller one.

But, so long as primer pockets are not expanding and everything else seems fine, you should be okay. Your velocities are hardly less than you could get with the somewhat larger .204 Ruger with considerably more powder (and barrel heating and muzzle blast), so I think you should be very happy.

 

[Branxhunter]

I picked up this blank for the Sako (price includes machining):



And it was turned into this:



Since the photo I have inletters for the action, reshape the forend and generally sanded to remove the last of the router marks. I still have to open up the ejection port slightly and get it bedded before I start piling it up.

Marcus

 

[pepperC]

Marcus,
Congratulations on a wonderful rifle! I have been following this post with interest. Sako and small caliber...does it get any better??
That is stunning piece of timber. Who cut it for you?
I really like the look of your stainless tube on the blued action.
Great post. Dare I say this cannon will look better than an original off the line from Finland!!!
C

 

[Branxhunter]

I've been working on the stock for a few weeks - up to #600 grit wet and dry paper with the Organoil.

These first three pics are after the first coat of oil:








This from the weekend - the sun was shining and I had a spare half an hour, so dropped the metalwork into the stock and snapped off a few pics - here's one of them

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Marcus