July 23, 2021
The Canadas were shy this season. Maybe they imprinted our Center Pit last year, but they came close enough and the shot folded the big honker like a cheap suitcase at about 35 yards. The day was windy, so when the pit cover flew open they skedaddled fast, but not fast enough for a load of MIGRA (as in Migration) ammo.
Talking with a couple ammo guys I know at SHOT Show, one told me that he had seen some of this new ammo on a dealer’s shelf in the south. MIGRA’s claim to fame is their stacked load. The ones I tested combined No. 4 under No. 2 steel shot. The idea behind a stacked load is that the larger, hence more dense pellets, carry a lot of the killing power while the smaller pellets fill in the pattern, but with a little less whap.
The Combination Equation
Combination loads are nothing new. In the late 1970s Remington came out with their Duplex load that put No.'s 1 and 3 in one loading and No.'s 2 and 4 — labeled 1 X 3 and 2 X 4 — in the other. They lasted a few seasons, but no real benefit was ascribed to them and they quietly rode off into the sunset. Prior to the Duplex’s debut, some shotgun writers boasted of more lethality with mixed-pellet loads, but they simply stirred a bunch of No. 4 into a pot of No. 2s, which ended up not gaining much of anything.
In running the MIGRA load’s ballistics with my KPY ballistic computer program the performance of the two pellets becomes clearer. My ballistics engineer friend from one of the big ammo companies said, “They did it right by putting the smaller pellets on the bottom and the larger in top. That way the big pellets don’t have to fight their way through the smaller ones.” My calculator put the two different sized pellets on target at 40 yards with both retaining enough lethality both in pellet energy and terminal velocity.
Ballisticians agree that a pellet must be moving at 600 fps at the target with a combined 1.5 foot pounds of energy to kill something. The No. 2 came in with 2.82 ft/lbs and the No. 4 at 1.83 ft/lbs at 40 yards. The time difference between the two pellets in hitting the target is 24 thousandths of a second, but who’s counting.
I shot MIGRA’s 2s and 4s over my Oehler 35P chronograph and surprisingly the average of the five-shot string was 1,425 fps; within 5 fps of the 1,430 fps velocity printed on the MIGRA box. It is highly unusual for any shotshell to finish right at the printed velocity, as many factors govern the data: Barrel length, temperature to a slight extent, bore diameter, bore shape i.e. lengthened forcing cones, choke constriction and shell construction are all factors that govern measured velocity. In the end, unless you get a squib load where something went wrong in the loading process you’re in good hands with 1,430 fps. The MIGRA loads ran all the way from 1,246 fps to 1,557 fps, but the average of the five-shot string was 1,425 fps.
Stack the Odds in Your Favor
I also shot a series of patterns with the MIGRA 3-inch stacked-steel loads using my Remington VersaMax with a cylinder bore diameter of .733 and a Muller UFO extended choke tube with a constriction of .048 inches, i.e. extra full. I hand-counted the pellets; if you’re crazy enough to do this, spend $10 online and buy a pharmacist’s pill counter, which makes it far easier. I counted 68 No. 2 pellets and 145 No. 4s for a combined total of 213 pellets. The nominal charts place them, respectively at 62 No. 2s and 143 No. 4s; the slight variance is more than acceptable. The patterns averaged 160 pellet strikes within the 30-inch circle of lethality for a 75-percent pattern, certainly full-choke, and in terms of lethality, if you put this pattern on the bird like I did on several this season, it’s a dull day for your retriever used to chasing winged birds.
So what’s the verdict? I’d say that MIGRA has done what they set out to do and that is produce a shotgun shell capable of killing ducks and geese within good shooting range; 40 yards. Once we begin stretching beyond that distance no matter what the formula patterns thin and pellet velocities drop off quickly. At 55 yards both pellets drop below the 600 fps threshold velocity required for a good kill — No. 2's are at 561 fps and No. 4's, 500 fps — although the No. 2 pellet does carry through on pellet energy at 2.46 ft/lbs. Still, as was once determined by a test of shot shells at Winchester’s Nilo Farms near East Alton, Illinois where we shot flighted mallards at marked distances out to 60 yards, it was universally decided that it is harder to hit a duck at 40 yards and beyond than it is to kill it. Use whatever shells you like, but spend time practicing so that when the moment comes you can hit the duck or goose good and square and really drop it.