Pellet testing for a BSA R10

[Mole2017]

While on vacation visiting family up north, I spent some time with my R10 trying to figure out which pellet it liked best. Thought I'd share the results (and experience).

Early testing after I got it working properly (purchased used—the regulator turned out to be seized) was not promising--this PCP did not automatically let me shoot better than I could already shoot with my Gamo (a springer), but I suspected I just needed to put the time in to check more than just the Gamo's favorite pellets. The crown checked out ok, but a final cleaning did find a lot of dirty oil in the barrel. There was not much else left to do but get to work on the pellets…

The range was about 22 yards, shooting from a crouching position from an open window with a so-so bean bag, which is to say there may be some technique errors lurking in this data. The target sheets were 8.5”x11” card stock with a dozen 5/8” bulls that I designed a few years ago when I was sorting out the Gamo. The pictures below are from scans of those sheets, cut and pasted together to give me two pictures to post. The scope was at 16x.

Looking at the “first round” picture, you’ll note that rather than write the whole name of each pellet on each bull, I’ve written just a letter or two (the list is below). The very first bull was some testing with the Gamo, so ignore that. I did put 8 or 10 “F” pellets into the second bull, but all others were 5 shots for each of over two dozen pellets (That was one heavy box to pack for the trip!). No sorting or weighing done here.

And in that first row, we have exactly why we do this sort of testing: F was terrible, but A was promising. Those of you with more experience might see vertical groups and horizontal groups in this picture—I suspect bad technique contributing to things here, but then again, some pellets seemed immune. This was a PCP, but while there I also tested a neighbor's Crosman Nitro Venom Dusk that was somewhat sensitive to how I held it and not at all broken in yet--and it showed!

From these results, I picked those pellets that seemed promising for another round of testing, giving us the “finalists” picture. I wasn’t rigorous in this selection process, but some were obviously doing better than others, and others were a maybe. Note that while the performance was mostly similar to the first round of testing for each pellets (except for T…the best one in that group was actually a V—I lost count and put the first one in the wrong bull), the point of impact moved for a few of them: I suspect that after so many shots from this window, I was getting used to things and maybe my technique was settling or at least coming together for some of them.

From these finalists, which would you pick? (Hint: which one seems “ready to go” without any more adjustment to the scope?) V was somehow dead on in this final round and subsequent pest control at my father-in-law’s house showed it: it seemed I couldn’t miss with this pellet. Nailed a chipmunk at 40 yards (several others at closer ranges) and smaller pocket gopher at 41 yards.

Takeaways from this testing:
1. Do your testing in a shooting position/set-up that you are comfortable with and that isn’t causing problems itself. I was actually pretty green with this rifle and this perch at the window wasn't naturally easy, but things felt better after a while.
2. Be prepared to repeat tests.  Now that I’m back home, I’m thinking I should revisit some of these pellets to make sure. Did you notice I skipped M? I’ll have to test those against the others sometime (There is no “I”—I left that out of the naming sequence).
3. The old usual warning: some guns like some pellets and not others. My Gamo loves R, N and H, but hates A.
4. Don't attempt this until your gun is broken in and operating consistently.

I’ll leave it to other to make more observations (or ask questions).

Here’s the list of pellets for those of you that want to know (letter, name, weight and head diameter, if noted)
A--AA Diabolo Field, 8.44, 4.52 mm
B--AA Diabolo Field, 8.44, 4.51 mm
C--Beeman coated hollowpoint, 7.2
D--Beeman coated wadcutter, 7.7
E--AA Falcon, 7.33, 4.52 mm
F--Crosman Competition blister pack, 7.4
G--Crosman Premier Super Match, 7.9
H--Crosman Premier, ultra magnum, 10.5
J--H&N FTT, 8.64, 4.50 mm
K--JSB Match Diabolo Exact, 8.44
L--Promethius hunting
M--RWS Diabolo Basic, 7.0
N--RWS Meisterkugeln, 8.2
O--RWS Superdome, 8.3
P--H&N Sport, 8.18
Q--Beeman H&N Match, 8.18
R--RWS Supermag, 9.3
S--H&N Excite Neue Spitz., 8.49
T--Winchester, 9.71
U--Skenco Golden Match Type 4, 9.26
V--Crosman Premier hollowpoint.177 Cal, 7.9
W--JSB Exact Beast, 16.20
Z--Beeman Crow magnum, 8.8
AB--H&N Crow Magnum, 9.26
AC--Predator Polymag Shorts, 8.02
AD--Predator Polymag, 8.0
AE--Daisy Avanti Diablo Match, 8.4

[renowntwo]

Nicely done. Keep at it, I'm sure the next pics you post will be better as you learn the AR and what pellets you decide to use.

[Mole2017]

Uh-oh...another takeaway: Get a chronograph...

I just did some acoustic velocity measurements with the "V" pellet--the Crosman Premier Hollow Point. A killer for sure and really accurate, but the average speed over about 9 yards was 950 FPS. That puts the muzzle velocity closer to 975, which seems a little higher than ideal for accuracy. A heavier pellet like the RWS Supermag does indeed hit just over 900 at the muzzle, but this result would suggest a number of my pellets might have fared better if the velocity wasn't as high. Something to look into, I guess.

By the way, I found a few omissions in my list--you don't see names for X and Y, which made it to the finals, and AA; somehow I hadn't marked them yet in the spreadsheet when I dumped that list. They would be
X--H&N Baracuda Hunter Extreme, 9.57
Y--Beeman Kodian Extra Heavy, 10.65
AA--JSB Ultra Shock, 10.34
All heavy pellets, too. Hmm.