Pellet weight variance question [Air Rifle]

[Jeffery8mm]

My daughter is involved in 4H shooting sports, 10 meter air rifle. This is our first year and so far we are doing well. She has a Daisy 953 with the Avanti diopter sights. My question relates to the pellets. How much variance is acceptable , or is going to make a difference at 33 feet. I weighed a batch of pellets on my Pact digital scale and all ran from 7.8 to 8.2, with most being under 8gr. Am I being too OCD?
Thanks
Jeff

[AZ-Stew]

Sort some by weight and see what kind of accuracy you/she gets. Shoot several groups using batches of pellets in the same weight category: Some at 7.8, some at 7.9, etc. Shoot several groups at each weight increment and record the results. As far as I know, there's no other way. If sorting doesn't matter, just hand her the can of pellets and let her go at it. It may give her a psychological advantage to believe one weight of pellets is more accurate than another. She may concentrate on the shooting basics more intently if she thinks her sorted pellets give her an advantage.

Regards,

Stew

[Doc Highwall]

You have to take into consideration the capabilities of the gun and the shooter. I would first test the gun in a no wind condition at 10 meters or as close as possible like your basement or garage with a rest. If you find that the weight variance does not make a difference great. Next with the rifle on the rest play with different front apertures to see what she shoots best with. The white around the target in the front aperture should appear to be about half the target size. Example, say you are shooting the 100 yard small-bore target at 100 yards that is 8" in diameter, half of that is 4", 8"+ 4" = 12" or 2" of white all around the target. This is the smallest front aperture that should be used. Also what position is she going to shoot?

[scrapcan]

What pellet are you guys shooting? Based on the weight you gave I would say you are shooting .177, is that right? Crossman premiers or JSB exacts are ones I would try.

Some times the quality of the swage pellet is more inportant than a small wieght variation. This is especially true of having a good skirt on the pellet. You might also try a tool that uniforms the skirt so you get a good seal.

[Jeffery8mm]

As of now we are using the .177 Daisy Precision Max. Their version of a match pelllet.
I want to try a true match pellet in the NEAR future. I think I can get the premiers locally!!
Thanks
JEff

[Blacksmith]

Jeff
Air rifles like .22's are ammo sensitive. Do some ammo testing of different brands and styles. Since she is shooting in competition check the rules first to see what is legal. Then shoot groups from a rest with every different brand, style, weight you can get and find what works best in her gun. In our testing certain guns like certain brands and some guns prefer a lower cost pellet to the expensive match pellets. For some of our guns we settled on a lower cost pellet for practice and a higher cost pellet for matches other guns are happy with a medium cost pellet for everything. You have to test to be sure what is best in your particular gun.

Blacksmith

[Doc Highwall]

I also used a small ball to seat the pellets into the barrel of my Anschutz 2002CA to get it to shoot the best. I use to get my pellets from Champions Choice made for them by H&N in both 4.48 mm and 4.49 mm.

[Larry Gibson]

Whether or not segregating pellets by weight will have any effect on accuracy does indeed depend on the rifles capability to use the difference the accuacy makes. Then if the air rifle can tell the difference will the shooter be able to take advantage? Both of these have already been mentioned. Serrious match shooters use pellets that are uniform as to diameter and weight, even the 10 meter shooters. Field target can be much more demanding. I conducted a test some years back to determine the very answer to this question for myself. I would not shoot a serious field target match without using weight segregated pellets. While my test are with a .22 cal pellet and rifle they also apply to my .20 cal and .177 cal pellet rifles.

Larry Gibson

Below is the results from my test;

.22 cal RWS M54 / Chronograph Results and Pellet Weight Variation
By Larry Gibson

As it was a dreary drizzly rainy day, I decided to conduct a test of various .22 caliber pellets in my RWS M54. The wife had left to visit her mother and had forgotten to leave me with any "honey-do's". AH HA, a free man left to my own devices! With the spring being recently replaced in the M54 it seemed like a good time to do some chronographing. Sorry, you high "tuned" guys, it was just a factory spring. Since the spring replacement I have shot it just enough, perhaps 100 shots, to zero it at 50 yards then dispatch 4 rats and 5 pigeons.

Anyway, I proceeded to set up my "home range". I use the kitchen counter for a benchrest. This enables me to shoot out through the open sliding door into a pellet trap (large dead Fir) about 17 yards away. I set the chronograph on the deck just outside the door. Incidentally for those interested in silencers, a house makes a dandy! The neighbors are oblivious to what I'm doing. Only one problem though, kind of hard to attach to the barrel and carry it around. Oh yes, expensive too!

This makes for a pleasant day "at the range" so to speak. Just put a little easy listening on the BOSE, pop the top on a cool one (Diet Coke for me) and just enjoy! Well, except for the occasional obnoxious telephone solicitor.

Enough of the aesthetics, let's get to the technical stuff. As I said the bench (counter) was solid and I used sandbags front and rear. The Oehler M35P with 24" screen spacing was set up with the center of screen spacing 15' from the muzzle. Temperature was 64 degrees with 60% humidity. All pellets were tested in 10 shot strings. Ten pellets were weighed together then divided by 10 to get an "average" weight. The pellets tested were simply those pellets I had on hand. All were within factory recommended weight except the Crow Magnums. I chose not to test the Kodiaks as they aren't stabilized by the twist of this barrel and are heavier still.

Chronograph data:
(AV = average velocity / ES = extreme spread of velocity / SD = Standard Deviation / all velocities are in FEET PER SECOND, fps)

Crossman Premiers / 14.2gr / 804 fps MV / 20 fps ES / 5 fps SD
10 shots; 810, 807, 813, 806, 793, 806, 799, 800, 808, 806

RWS Meisterklugln / 13.8gr / 811 fps AV / 9 fps ES / 2 fps SD
10 shots; 810, 811, 811, 817, 811, 809, 808, 810, 810, 815

RWS H-Points / 14.3gr / 794 fps AV / 13 fps ES / 3 fps SD
10 shots; 788, 793, 797, 796, 801, 796, 795, 793, 796, 794
Beeman Silver Arrows / 17.1gr / 708 fps AV / 13 fps ES / 4 fps SD
10 shots; 706, 714, 701, 704, 708, 713, 710, 712, 708, 708

Beeman Silver Stings / 15.7gr / 755 fps AV / 21 fps ES / 6 fps SD
10 shots; 754, 759, 763, 752, 758, 742, 755, 759, 760, 751

Beeman Silver Bears / 12.5gr / 832 fps AV / 13 fps ES / 4 fps SD
10 shots; 833, 826, 835, 833, 830, 836, 839, 828, 831, 838

Vortex Lamprey / 16.4gr / 704 fps AV / 33 fps ES / 9 fps SD
10 shots; 696, 720, 707, 709, 708, 687, 695, 708, 702, 712

Beeman Crow Magnums / 18.2gr / 674 fps AV / 12 fps ES / 4 fps SD
10 shots; 678, 680, 668, 677, 678, 668, 674, 677, 668, 677

I was surprised at the 20 fps ES of the Crossman Premiers. As they have proven to be the most accurate and effective for hunting across the ranges I've used them (to 70 yards), I expected them to be closer to the Meisterklugln Match pellet. Noting that two shots dropped down into the 790's I wondered if pellet weight variation might be a significant factor here. There was only one way to find out - weigh individual pellets. Not a fun thing.

I used an old Redding scale I've had for years. The beam swings smoothly and freely and it has always proved accurate against certified weights. I have outlined it on the loading bench so it is always used consistently in the same place. I've drilled a hole in the bench to put the handle of a magnifying glass into. This puts the glass inline with the scale's markings and makes them real easy to read accurately. I can weigh pellets accurate to 1/20th grain this way.

I set the scale for a weight of 14.2 gr. Then using the scale markings I weighed 50 Crossman Premiers with the following results:
Weight # of pellets
14.05 gr 3
14.1 gr 5
14.15 gr 6
14.2 gr 15
14.25 gr 7
14.3 gr 6
14.35 gr 7
14.4 gr 1

There was a 3.5 tenths of a grain or 2 1/2% variation among the 50 pellets. The obvious question was; would a 2 1/2% weight variation really effect velocity? If so, then testing one of each weight from the lightest to the heaviest should show a trend of velocities getting progressively slower. I conducted the test with these results:
Pellet/weight fps
14.05 817
14.1 815
14.15 809
14.2 810
14.25 807
14.3 790
14.35 795
14.4 801

We see here a definite trend of descending velocity within expected shot to shot variation. This did indeed demonstrate a lower velocity as the pellet weight increased. This was with only a 2 1/2% weight variation. My next hypothesis was; a 10 shot string of equal weight pellets should have a very consistent ES with a low SD.
I then tested ten of the pellets that weighed exactly 14.2 gr.

RESULTS:

Crossman Premiers / 14.2 gr weight exact / 805 fps AV / 5 FPS ES / 1 fps SD
10 shots; 807, 807, 804, 807, 807, 805, 805, 806, 802, 807

This is extremely consistent and proved to be the most consistent of any 10 shot string I have chronographed to date. A test of accuracy differences between weighed and selected Vs unweighed straight out of box pellets (Crossman Premiers) is scheduled in the near future. I suspect a measurable difference in group sizes will occur at ranges of 30 to 70 yards. Weighing pellets can be extremely tedious, however it may be worth the effort if shooting at the longer ranges. Only testing will tell.

The day has turned out to be enjoyable and productive - knowledgewise anyway. Hope this has been of interest to some.

Good luck, good shooting and good hunting


.22 Cal RWS 54/Crosman Premiers – weighed/tested at 10 to 90 yards
By Larry M. Gibson

Television had little on that I found interesting several evenings ago. So I began another tedious and boring project, weighing pellets! My method was as described in a previous posting, “.22 cal RWS M54/Chronograph Results and Pellet Weight Variation”, on 8/16/99 at 00:56:43. In that article I described how the weight variation of Crosman Premier .22 cal pellets had a most decided effect on the chronographed extreme spread and standard deviation in feet per second of 10 shot strings. I hypothesized that same weight pellets Vs “out of the box “ pellets would result in a measurable difference in group sizes at ranges of 30 to 70 yards. Thus began my quest to weigh and test.

I weighed 230 CPs out of a box marked “Die #1” dated July 30 1996. I also opened a new box of CPs marked “Die #1” dated Feb 25 1999 and weighed a sampling. The pellet to pellet weight variation was similar between the two. The chart breaks down by weight in grains (gr) the number of each weight and the percentage each weight was of the total.

Gr-------#-------%
14.0-----3-----01.3
14.05---27----11.8
14.1-----43----18.7
14.15---53----23.0
14.2----57-----24.8
14.25---25----10.8
14.3----18-----07.9
14.35----4-----01.1

Again I found 3.5 tenths of a grain weight variation or 2.5%. To keep vZc happy I used a micrometer that measures to .0001” and measured a sampling of each weight at the head and skirt diameters. Frankly, I found the diameter variations measured on different points of the pellet diameters to be greater than any variation of diameters between different weights. Since I already own the barrel and have purchased the pellets, meaning I’m going to shoot them, the real meaningful measurement is going to be group sizes. Sorry vZc!

The next night I was able to conduct the shooting portion of the test. I have access to a building where I can shoot to 90 yards. I used a 6 foot folding table for a bench rest with sandbags front and rear. A cardboard box with a face 30x30” and 12” deep stuffed with old phone books was the pellet trap. This made it handy because I used a Bushnel Pro-800 range finder to set the box at all ranges tested. I use the range finder when hunting so it validates the holdover data for practical use. I use a Magic Marker to make a + on the backside of regular target paper for aiming points.

I used my RWS M54 with a RWS 450 3x9 riflescope (set at 9x) to conduct the test. All testing for group size of the weighed pellets was conducted at a range of 50 yards. I fired a 5 shot test group with each weight of pellet except the 14 and 14.35 grain weights. I only had 3 and 4 of each weight respectively. Also a “control” group of 10 pellets “out of the box” was fired. The chart lists the center to center group size for each weight pellet.



Weight Group
grains Size

14.00---------.22”
14.05---------.53”
14.10---------.6”
14.15---------.76”
14.20---------.54”
14.25---------.66”
14.30---------.47”
14.35---------.56”

Average group size for the 8 groups: 0.5425”

The 10 shot control group measured 1.5” center to center. Seven of the ten were in a 0.85” cluster. There were three “flyers”, one high and two low that opened the group. Obviously sorting the pellets by exact weight produced superior groups and accuracy. The question was; what weights produced the 7 shot cluster in the control group and which were the flyers?”

Looking at the target it was easy to see the center of three test groups coincided with the center of the 7 shot cluster of the control group. The weights of those groups are 14.10, 14.15 and 14.20 grains. Those three weights composed 66.5% of the pellets. Not surprising, the centers of the 14.00 and the 14.05 groups were high and the 14.25, 14.30 and 14.35 groups were low. Over laying all 8 test groups (37 shots) using the aiming point as a reference produced a composite group of 1.65”.

I then took the remaining 14.10, 14.15 and 14.20 grain pellets and mixed them up. The rifle was then zeroed at 50 yards with the point of impact being 0.3” above point of aim. The target box was then moved from 10 yards to 90 yards in 10 yard increments. The riflescope was not adjusted other than the focus at each range. This gave me the exact trajectory of this pellet. I prefer to use hold off for elevation and wind when hunting. The group sizes then give an indication of the vital area of a small game animal I can reasonably expect to hit from a solid rested position. The chart lists the trajectory and the group (5 shot) at each range.

Range
Yards--------0---10---20----30----40----50-----60----70-----80-----90
Trajectory
Inches-___-2___0_+1.1_+1.6_+1.6__+.3__-1.9__-5.1__-10.2_-20.0

Group
Size________.15”_.20”__.35”_.45”__.56”_.78” _1.08”_0.85”_ 3.0”


On the 90 yard group I ran out of weighed pellets so I shot it with pellets out of the box. The group was 1.3” wide with the expected vertical stringing being 3”.

This test has validated my original conclusion that weighing and sorting CPs is an erstwhile, though boring, endeavor. This is especially the case if one is shooting targets or hunting at ranges further than 30 yards. If just plinking “out of the box” will do nicely. Excuse me while I go weigh pellets. However, 1.5” ten shot groups will do for most hunting inside 50 yards. Perhaps it’s “Miller time”. Where did I leave that TV Guide anyway……..

[HORNET]

Nice write ups, Larry. There are implications for weight sorting boolits for serious matches.

[R.M.]

Contact Scott Pilkington in TN. He deals in Int'l guns and equipment, and manufactures match grade pellets for a decent price. Great guy to deal with also.

http://www.pilkguns.com/