.222 Rem Mag Imp
The May 6-9, 2002 Don Bower Long Range Shooting Clinic held at Alliance, NE was a blast. For now, I'll let others who attended report their impressions elsewhere, but I'd like to report briefly on the 11th hour short session on the range with my .222 Rem. Mag. Imp. 16 3/4" long x 1" diameter barrel with the fast 1-7" twist rate.
My focus was not shooting, but rather observing and getting pictures. However, I did take the barrel with me in hopes of tossing some ammo together there at Alliance and giving the newly made barrel a "test drive" at long range.
The evening before I left, I worked up 2 max. loads with 80 gr. Sierra BTHP Match bullets and H380 & WW-760 powders with CCI Mag. small rifle primers doing the shooting in Marc Sheehan's steel pipe test fire tube in his basement, which was quite interesting and has a lot of potential for others who have difficulty getting to a range for such work. If he gets a website up, perhaps we can impose on him to show & explain it.
Left to right:
Standard .223 Rem.,
.222 Rem. Mag.,
.222 Rem. Mag. Imp. with 80 gr. Sierra,
and 5.6x50 R Bellm
Several things should be noted with these rounds standing side by side.
First the comparative difference in length between .223 Rem. and .222 Rem Mag. It is this difference in length that permits cutting out factory .223 Rem. throats in the process of rechambering the longer Mag case.
Second, note that the .222 Rem. Mag Imp. case is a tad shorter than the parent .222 Rem Mag case. This is due to the case shortening when fire formed to the larger diameter. Note also the the Imp chamber must be cut for the full length standard case, and that case length of the Imp. can be allowed to grow back to original Mag. trim length.
Third, note that a hybridized .222 Mag Imp can be had with a short neck like the 5.6x50 R Bellm by setting the chamber up to headspace on the case mouth instead of the neck/shoulder junction for fire forming, thus blowing the shoulder forward. Case length must be pretty precise to do this. Capacity can be increased substantially while still using common, economical .222 Rem. Mag. brass. Body length v. neck length can be whatever you want it to be.
Fourth, these cases share common dimensions and allow for cross-overs with dies. For example, you can size and load .222 Rem. Mag. with standard .223 Rem dies. .222 Rem Mag dies work for the standard 5.6x50 R case. In both of these instances, just back the dies off accordingly. .223 Rem Imp. dies work for .222 Rem. Mag. Imp. and are what I am loading the Imp. with. These same dies work with the 5.6x50 R. Bellm since .223 Rem Imp, .222 Rem Mag Imp. and 5.6x50 R Bellm chambers all share the same .370" shoulder diameter.
Note that the total body taper of the long bodied 5.6x50 R Bellm is only about .006." You cannot squeeze much more into a 3/8" diameter chamber than this, with the exception of the slightly smaller diameter 6mmx70 R or 6.5x70 R European cartridges which are longer than .30/06s by 7mm! I have not chambered for these and may never, but the thought is intriguing.
Within normal tolerance variations, all of these cases pictured share the same head diameter, and of course can operate at the same 55,000 psi, plus, pressures without risk of stretching the Contender frame.
With the combination of 5.6x50 R Bellm cases and .223 Rem. Imp. dies which are too short to reach the web of the case, WHEN the web needs to be sized, run cases through a Lee carbide .357 Mag size die after first drilling out the top of the die to clear the longer body of the 5.6x50 R case. I do this no charge if the die is supplied at the time I am doing the rechamber. It also lets me verify that the .357 Mag dies sizes small enough. I specify Lee carbide .357 Mag dies because some .357 Mag. size dies do not size small enough. Lee nearly always does.
Fifth and final point. Even though the
5.6x50 R brass is somewhat expensive, a couple hundred new cases and a
rechamber job is still less than the cost of a new barrel if an existing
.223 Rem barrel is shot out. Rechambering a shot out .223 Rem barrel
to the longer case, either standard and using the same .223 Rem dies you
already have (plus a .357 Mag size die as needed for the web area) or the
Bellm-ized version for .22-250 performance, puts you back into operation
with restored accuracy and much improved performance. Something to
keep in mind.
Next morning after a lengthy final after-breakfast meeting at the VFW, part of the group left to go shoot self-erecting, biodegradable targets, otherwise known as prairie dogs. The rest of us went to the range.
I had the privilege of having Don scope for me as I sighted in the used 10x Burris I had mounted on the barrel the night before. BTW, as is normal practice, I was sighting in at 500 yards on ram targets. I quickly discovered that whoever had used the scope before had cranked the windage all the way to the left so hard that it took both hands on a big screwdriver to crack it loose. Whoever it was that did this, I'll bite my tongue and save my comments about his ancestry.
From shot to shot under Don's directions, I managed to get the scope on close enough that he told me to "Go to the Post." This is not for 20 lashes or anything like that. The post is a white 3" angle iron with the edge pointed toward the firing line 660 yards away. The objective is not to just hit the angle iron, but to "split a bullet" on the edge, which was done several times during the 4 day seminar.
Starting from zeroing to shooting at the post, my 11th shot, total fired to that point, came within about 3/4" of the edge, and time for closer examination/photo opportunity. See the picture. Don should have been in the photo also. Guess I'll have to go do it again and make sure he is in the picture.
I believe it was Ernie Bishop who made the "split" on the upper part of the post he was holding on.
The strong cross wind was bothering Don's strained eyes, so he asked the new head of his long range shooting regimen, Marc Sheehan of Alliance, NE to spot for me while I tried for the edge again. At Marc's direction, rather than changing hold on the post, Marc said to give it a click to the right. Now it was shooting about a foot to the right, and no amount of twisting the windage adjustment was affecting any change of impact. To verify it was not just operator error, I had the much more seasoned Marc shoot it also while I spotted. He did as I did. He held a nice group in the dirt about a foot to the right of the post, confirming my suspicions of damage to the scope by the previous user.
By this time, I was already past due leaving for home, and called it quits.
The short test drive with this barrel made from a Hart benchrest blank was quite encouraging.
I had been wanting to test my theory (since the clinic Don and I put on in '99) about what could be done at long range using this small diameter, relatively high case capacity cartridge and high ballistic coefficient .22 cal. bullets. One thing we noticed right off is the noticeably shorter time of flight it had compared to what one normally gets from maxed out 7mm and .30 caliber cartridges permissible in the Contender. The time between the bang of the gun and hearing the "clank" on steel is much shorter. And the strong cross winds at about 30 mph were a good test of the .22 cal. bullets.
Bottom line is that in AR-15 and bolt guns alike, the heavier .22 caliber bullets are making more of a showing in long range competition all the time, and they have application in the Contender also. I was told recently that a bolt action 24" .223 Rem shooting 70 gr. bullets had beat a field of 80 .308 Win rifles at 1000 yards. I did not get the details, but have no doubt the .22s can hold their own.
In the Contender, the problem is that large diameter chambers restrict one to lower pressures, and whether shooting small diameter or larger diameter bullets, one is still handicapped when it comes to velocity. BUT, when going to small diameter chambers, the pressure limit is whatever their brass will stand, 55,000 psi or more with no risk to the frame.
The .222 Rem. Mag. Imp. case will hold up to about 33.5 gr. of some powders, which is significant. Chronographing my 2 loads back home, I got 2700 fps. with the WW-760 load I shot at Alliance and 2800 fps. plus with H380, using 30 gr. of each, and H380 showing a tad higher pressure than 760 did. Loading 760 to the same pressure indications can be done and may give equal velocities.
Looking at the manuals, what I had achieved with the increased capacity of the .222 Rem. Mag. Imp. v. the .223 Rem. was enough capacity for enough slower powder (otherwise too bulky to stuff into a .223 Rem case) to give the same or better velocities with 80 gr. bullets in a short 16 3/4" barrel as Hornady for example showed with 75 gr. bullets shot from a 24" barrel. Not a bad showing for the first try.
Other powders need to be tried, of course, and while the 80 gr. Sierra made a good showing, I am wondering if I should not have tripped over the 70-75 gr. match bullets which would favor higher velocities perhaps exceeding 3000 fps. from this same barrel.
At Alliance, most of the guns being shot were from longer barrels and things like Encores and XPs that permit more muscle than Contenders handle.
So, why dink with the Contender? I was trying to stay traditional. Don's earlier work and original claims to fame were centered around 14" Contender barrels and, later, longer Contender barrels. It was within these parameter restraints that I laid out the challenge to achieve the most that could be achieved. And as always, it was to be done without going crazy with expensive brass and custom dies costing more than necessary.
I could have used the 5.6x50 R Bellm case which will hold up to 37 gr. of powder and permit the same pressure levels as the .223 Rem. and .222 Rem. Mag. Imp. But brass for the 5.6x 50 R ranges from about $69 to about $125/C. .222 Rem Mag. brass is $20 or less and of good match quality to boot.
Dies for the Imp.? I used the slightly shorter .223 Rem. Imp. Redding dies I bought from Lock, Stock, and Barrel for $54, higher than common dies, but not unreasonable for the loading opportunities it offers.
If time permits, I may put on the buttstock and 4-12 Leupold rifle scope before the 10x Burris comes back from repair, but I will be doing more work with this barrel as soon as I can.
Essentially equaling .22-250 Rem. performance, .222 Rem. Mag. Imp. has proven itself very well in slower twist barrels in the 1-10," 1-12," and 1-14" twists I have chambered it in, and it is showing a lot of promise with the heavy bullets.
I think I am on to something.
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