One for the 20/222 fans.

[Camel]

Tony, I haven't tried any other powder than 2207, it just works so I didn't see any point in trying anything else, if I had some Rel 7 I would have given that a run, and probably would be still using it, Im pretty conservative in my load development, don't generally try other things when something is working, cant see the point. I have never even tried different primers in the same cartridge, for anything, generally get what is readily available, and has a good reputation, then stock up. I have only ever used Rem 7 1/2 primers in cartridges that take that size, same with large rifle primers, its always been Rem 9 1/2, I do have some small and large Fed primers in the cupboard that have been there for over 20 years, shit, some probably longer, not enough to bother working up a load for.

Your WW cases might have a bit more capacity than my Lap, whats the water volume ? Ill check one of mine later on today while loading another batch.

Reckon there is one fella down in SW Victoria who is lapping up all this information, Hello Marcus

[MISSED]

I used RE7 in my 222 for years I switched to ADI and would never go back.

Main reason being is that RE7 is a fairly dirty powder

[Tony Z]

Finally settled on primer and powder choices for the 20-222 after testing over the last two weekends.

The primer test went with the WSRs producing half inch groups consistently with either the 32 Zmax and 40 Vmax. The group discrepancy by altering primer brands was quite stark with the Rem 7 1/2s doubling the group size. Fed 205Ms were nearly as bad which is odd considering their virtual legend status in BR.
As for powder i opted to use 2207 simply because the likelyhood of a continuing supply of Reloder powders is looking shaky. 22.5 grains was the load i settled on for the 32s even though 23 grains shoots tighter. The 23 grain load was heading toward sizing the brass too often to keep a loose bolt close. With the 40s 21.2 grains shot just over half inch.
Now this is where it gets interesting. Seating depth alteration shows little change in group size or POI at a 100 yards. At 200 yards where all the final tests were done in some very good conditions, seating depth still showed no change in POI but gave distinct patterns in grouping. Jam the bullets and it shot horizontal lines like a wind read. Jump them more than 15 thou and it shoots vertical lines with literally each bullet stacked touching but in random order. The pic below shows the effect where i can assure there was no wind or mirage causing the pattern. The WSR group shown is at base setting of ten thou off the lands. Get them to 5 thou off the lands and it shoots a round cluster. That's where i ended. Both bullets and respective powder charges using WSRs shooting around the half inch but the 40s hitting a shade lower at 200 yards.

Typical of the T3 rifles i have or have worked with, the barrel cleans and shoots better once you get a couple of hundred rounds through them. Apart from the chamber, the only alteration this rifle has from new is the addition of pillars and a hardened recoil lug. If this rifle is like my 222 then i expect it to get better with a few more rounds through it.

[Con]

TonyZ,
You make reference to T3 barrels ... is that to say this is a shunted and then rechambered T3 factory varmint barrel?
Cheers...
Con

[Camel]

Tony, that seems to be going along alright, good stuff.
But why oh why did you have to put that bit about WSR primers giving you smaller groups compared to the Rem 7 1/2 ?? It will have me thinking about something I don't really want to think about, as I have over 5000 Rem 7 1/2 primers in the cupboard and was quite happy in my ignorance of what another primer could do. Some times I really hate blokes like you that cause these evil thoughts.

[Con]

The hotter primers have always been speculated to be 'upsetting' of accuracy at times. Flip side is if your pushing pressures, the thicker cups may be a safety margin. Was only reading last night of problems with the Rem 6-1/2 by the late Mike Walker ... that led to the development of the 7-1/2. I think nowadays the CCI450 is the thickest cupped small rifle magnum primer? The 22Hornet has also been shown to respond to softer primers at times.
Cheers...
Con

[Tony Z]

Hi Con yes a cut and shut brand new T3 varmint in 204.

Mark this is in this barrel only. The 7 1/2s may not work with the 20, but i have had success with them elsewhere. I have many primers of all brands and always run this same test. When i ran this primer test, i did simultaneously with my Ruger Hornet but at a 100 yards. See below. The CCI 400 group is what it is and not wind or errant. Primers not shown also tried in the Hornet were S&B small pistol, CCI 450, Rem 6 1/2s and BR4s. All were similar except when it came to the very old CCI 400s in the original small trays. That group was small by Hornet standards at around point four inch. It's not if the fire was started, but how said the investigator.
To expand it a little more with regard to something like my old 25/06 back in the late 80s. With the slower powders like the original 2213 it would shoot one group in five worth owning. The rest were horrid. Something i read about that cartridge in a magazine, those things before the intrawebbything, led me to try a magnum primer. CCI250s to be exact because i still have some of the remnants. That turned the whole thing around and loads previously discarded were now consistent sub MOA. Rifle long sold but experience learnt. Re22 has a reputation of being a bitch to tune and often referred to as temperature sensitive. I found it primer sensitive where once the right one is found, a very consistent powder in long barrels and heavy bullets as many yank 1K shooters found.

[Con]

TonyZ,
How short is the 24" tube now it's been shunted to 20/223, then 20/222? I'm seriously tempted by a local 'smiths accidental invention where he shunts a 204Ruger barrel to take a 222Rem, then shortens the 204Ruger dies to suit. So he ends with a shorter necked 20/222, with 30deg shoulder, shoulder getting blown forward during fireforming. A few local fox shooters have done the conversion, all being extremely pleased with the results. I'll be asking him to do the same with a 223AI barrel to give me a 222AI of sorts.
Cheers...
Con

[Tony Z]

Con i seriously looked at that same conversion. Did exactly that with my 17/222 by short chambering with 17 Rem reamer then just shunted a set of 17 Rem dies. Worked perfect to the point of no neck turn chamber on minimum dimensions all round. The only reason i didn't do it with the 204 was i know from many wildcats that a neck length of a caliber or thereabouts equals short throat life regardless of shoulder angle. If i had a reamer to lengthen the neck then i would have done it.
As for length of barrel lost overall. Started at 23 3/4" from factory and now is 22 5/8". Cut off the original factory threads then re-cut
with no relief to shoulder. No need to relieve a T3 barrel because the action is relieved. It was only a three mil loss from 20/223 to set back and re-time the 22 3/4" barrel.
This is the problem you might have. T3s now have relieved barrel threads. Earlier rifles did not. To shunt it to 204 short you will have 5mm to cut off then shift the shoulder. You either have a 7mm relief or no relief then 5 mm of new thread with a couple mil of no thread (original relief) then 18 mm of original thread. Both are ugly but hidden and really won't detract from the accuracy. Possibly. Me i can't sleep if i know it ain't right. This is another big contributor to why i passed on the idea and the fact i really hate 204 Ruger full stop.
Now when you want to do 20 PPC we should divvy up reamer cost. Just bought a Howa mini SS rifle for just such a project should we never see the 7.62x39 in the country. Cleavers is taking orders for them now i see.

[Con]

Can the relieved portion be overcome by taking all the threading off and recut a fresh 20/222 chamber, plus thread and fit? Ultimately, I want a 20" barrel anyway, but the T3 MT model doesn't come in 204.
Cheers...
Con

[Tony Z]

That is exactly what i did. You lose 25mm if all the thead is cut off. If the barrel isn't relieved from factory you lose 10mm or thereabouts depending on factory dimensions of the 204 chamber. Possibly less, possibly more.

[stinkitup]

Tony, that seems to be going along alright, good stuff.
But why oh why did you have to put that bit about WSR primers giving you smaller groups compared to the Rem 7 1/2 ?? It will have me thinking about something I don't really want to think about, as I have over 5000 Rem 7 1/2 primers in the cupboard and was quite happy in my ignorance of what another primer could do. Some times I really hate blokes like you that cause these evil thoughts.

Mark i have plenty of little winchester primers if you are chasing some. Just how to get them there. If your heading up Newcastle way they are here. hmmmm a trip south west shooting would be good though.
Ryan

[Camel]

Ryan, thanks for the offer mate, am not really that interested in trying anything else at the moment, found a load my rifle likes so am gunna stick with it. Whats the rule, one rifle, one load, so if I wanted to use another load I would have to buy a new rifle.

You are always welcome to come down mate, just drop me a line

[Tony Z]

Shot the 20-222 again over the weekend to confirm load and set zero to establish bullet trajectory. Final load is Win cases WSR primers 22.5 grains 2207 with 32 grain Zmax with a real world BC of 0.200. Zero is exactly one inch high at 100 yards then just a shade under point nine high at 200 yards for a dead zero at 230 yards. Point blank is 270 yards and at 300 yards drop is a shade under 3.8". Calculated velocity out of the 22 5/8" barrel is 3700 fps. Corrected to a 24 inch barrel would yield 3740 fps. Calculated to a 26 inch tube may see 3800. All well short of stated speeds overseas using 2207 regarded as the go to for top velocity. All stated I might add using a chronograph. Like I have said many many times and why I reverse calculate off emperical data, I have NEVER seen a fast barrel but I have seen many fast clocks. Only exceptions are the Ohlers. They don't lie. As much.

PS. The book BC for the V/Z max is 0.210. Real world has been stated at 0.200. At 0.210 the velocity is SLOWER!!! to match up to my data. To match it up to around 3900 fps the BC would have to be understated by around 20% or more. I highly doubt that is the case.

[MISSED]

Shot the 20-222 again over the weekend to confirm load and set zero to establish bullet trajectory. Final load is Win cases WSR primers 22.5 grains 2207 with 32 grain Zmax with a real world BC of 0.200. Zero is exactly one inch high at 100 yards then just a shade under point nine high at 200 yards for a dead zero at 230 yards. Point blank is 270 yards and at 300 yards drop is a shade under 3.8". Calculated velocity out of the 22 5/8" barrel is 3700 fps. Corrected to a 24 inch barrel would yield 3740 fps. Calculated to a 26 inch tube may see 3800. All well short of stated speeds overseas using 2207 regarded as the go to for top velocity. All stated I might add using a chronograph. Like I have said many many times and why I reverse calculate off emperical data, I have NEVER seen a fast barrel but I have seen many fast clocks. Only exceptions are the Ohlers. They don't lie. As much.

PS. The book BC for the V/Z max is 0.210. Real world has been stated at 0.200. At 0.210 the velocity is SLOWER!!! to match up to my data. To match it up to around 3900 fps the BC would have to be understated by around 20% or more. I highly doubt that is the case.

Intersting take on the BC.I emailed Hornady a couple of years ago questioning them on the speed that was used in their testing.The 32`s were tested at 3400fps.
Your speeds really do show how efficient the 20 VT is as mine has been over two different chrono`s on a couple of occasions at an average of 3850 FPS while using 4 grains less 2207