Become an AGN forum member to be included in our multi-thousand dollar Monthly Airgun Giveaways! Winning is as easy as picking a number, no strings attached! This is our way of thanking you for being a part of the worlds biggest airgun forum. Yours truly, Michael Wendt - Owner.
Join HERE

weighing pellets (yet again)

Views : 653 Likes : 0

Likes : 0

| Subscribe
July 25, 2021 at 10:30 am Link

Saltlake58
Participant

Member
United States
Accuracy: +64

So, I'm trying to tune my gun and the numbers are everywhere (well, not as close as they should be). Speed is varying about 3.4%, 812 to 840 fps. Average is right where I want it at 828, but want more consistency. Average weight is 34.01 (in this tin)

Then it hit me, I'm shooting straight out of the tin. The pellets are JSB 33.95 in .25 cal.

After weighing 120 pellets, I see a weight range of about 1.4 grains over 120 pellets. That's about 4%

So, the speed variance is 3.4% and the weight variance is about 4%. Seems like a pretty close relationship.

If I get some time to shoot in the next couple days, I'll run an experiment where speeds of lightest and heaviest are compared, try to validate how tight the relationship is.

Has anyone else already don the physical experiment and can validate the relationship? Saving me the time of doing so?

So, I'm trying to tune my gun and the numbers are everywhere (well, not as close as they should be). Speed is varying about 3.4%, 812 to 840 fps. Average is right where I want it at 828, but want more consistency. Average weight is 34.01 (in this tin)

Then it hit me, I'm shooting straight out of the tin. The pellets are JSB 33.95 in .25 cal.

After weighing 120 pellets, I see a weight range of about 1.4 grains over 120 pellets. That's about 4%

So, the speed variance is 3.4% and the weight variance is about 4%. Seems like a pretty close relationship.

If I get some time to shoot in the next couple days, I'll run an experiment where speeds of lightest and heaviest are compared, try to validate how tight the relationship is.

Has anyone else already don the physical experiment and can validate the relationship? Saving me the time of doing so?

July 25, 2021 at 10:42 am Link

18.13
Participant

Member
United States
Accuracy: +14

I don't remember the crony numbers but the poi was different. In. 25 cal the heavies hit low and the lighter ones hit high. But in. 22 cal the exact opposite heavies hit high

July 25, 2021 at 11:07 am Link

rsfrid
Participant

Member
United States
Accuracy: +4

For the reason you stated I weigh mine. I sort into batches of close weights (a few hundredths of grain) and keep shots for groups from same batch. I don't care if they are heavy or light, just that each mag gets taken from same batch. If the group is a bit high or a bit low doesn't bother me. Just that group is tight and Extreme Spread is lowest possible.

July 25, 2021 at 11:50 am Link

Saltlake58
Participant

Member
United States
Accuracy: +64

Those responses make me feel better, I'm not nuts thinking half a grain affects point of impact. I'll be shooting weighed pellets, maybe within 2 tenths to see if the chrony numbers tighten up later this week. I guess it's all part of learning these things. The complexities of airguns!

July 25, 2021 at 12:25 pm Link

rsfrid
Participant

Member
United States
Accuracy: +4

Saltlake58

Those responses make me feel better, I'm not nuts thinking half a grain affects point of impact. I'll be shooting weighed pellets, maybe within 2 tenths to see if the chrony numbers tighten up later this week. I guess it's all part of learning these things. The complexities of airguns!

I'd recommend keeping each tenth separate. Try that and see if you get tighter groups. I sort to like 5-6 hundredth.

Saltlake58

Those responses make me feel better, I'm not nuts thinking half a grain affects point of impact. I'll be shooting weighed pellets, maybe within 2 tenths to see if the chrony numbers tighten up later this week. I guess it's all part of learning these things. The complexities of airguns!

I'd recommend keeping each tenth separate. Try that and see if you get tighter groups. I sort to like 5-6 hundredth.

July 25, 2021 at 1:17 pm Link

18.13
Participant

Member
United States
Accuracy: +14

https://www.airgunnation.com/topic/should-you-sort-pellets-the-final-answer/

Baker Airguns just did a video on this

July 25, 2021 at 4:01 pm Link

jtnm
Participant

Member
United States
Accuracy: +6

I did this a couple years ago

July 25, 2021 at 4:48 pm Link

Saltlake58
Participant

Member
United States
Accuracy: +64

I weighed more pellets today. So far, the low is 33.1 with a high of 34.8. That's 1.7 grains difference in a 34 grain pellet. Yeah, that can make a significant difference in muzzle velocity and POI at a 100 yard target. 10 or 20 yards, maybe not, but at 100 where every minute thing is magnified, yeah, it'll make a difference.

I'll weigh up a couple batches, by 1/10 grain and do some testing this week. Could be interesting. Maybe there is a 1 to 1 relationship with weight and velocity. Maybe not quite 1 to 1, but close. but I'll bet there is a significant relationship.

I weighed more pellets today. So far, the low is 33.1 with a high of 34.8. That's 1.7 grains difference in a 34 grain pellet. Yeah, that can make a significant difference in muzzle velocity and POI at a 100 yard target. 10 or 20 yards, maybe not, but at 100 where every minute thing is magnified, yeah, it'll make a difference.

I'll weigh up a couple batches, by 1/10 grain and do some testing this week. Could be interesting. Maybe there is a 1 to 1 relationship with weight and velocity. Maybe not quite 1 to 1, but close. but I'll bet there is a significant relationship.

July 25, 2021 at 4:49 pm Link

Saltlake58
Participant

Member
United States
Accuracy: +64

jtnm

I did this a couple years ago

The video seems to bear out my concerns. Many thanks! Shows almost exactly what I've been seeing.

July 25, 2021 at 6:50 pm Link

thomasair
Manufacturer

Manufacturer
United States
Accuracy: +48

Turn the  hammer spring tension up some. You will likely reduce your spread considerably. Forget weighing to reduce spreads.

Mike

July 25, 2021 at 10:22 pm Link

Saltlake58
Participant

Member
United States
Accuracy: +64

Hammer is maxed. Absolutely no play in the hammer spring. The gun is a gen 1 Impact with some upgrades.

I weighed more pellets, and am amazed at the spread.

Lightest was 32.6 with heaviest at 34.9. that's nearly 7% of the advertised 33.95 weight. Only one each of the 32.6 and 34.9, but plenty in between.

Now that I have a bunch sorted, I'll chrony a test batch later this week (I hope, all depends on time).

Hammer is maxed. Absolutely no play in the hammer spring. The gun is a gen 1 Impact with some upgrades.

I weighed more pellets, and am amazed at the spread.

Lightest was 32.6 with heaviest at 34.9. that's nearly 7% of the advertised 33.95 weight. Only one each of the 32.6 and 34.9, but plenty in between.

Now that I have a bunch sorted, I'll chrony a test batch later this week (I hope, all depends on time).

July 26, 2021 at 8:04 am Link

thomasair
Manufacturer

Manufacturer
United States
Accuracy: +48

If you can’t raise the hammer….then lower the reg pressure.

Mike

July 26, 2021 at 10:09 am Link

bandg
Participant

Member
United States
Accuracy: +34

Saltlake58

Hammer is maxed. Absolutely no play in the hammer spring. The gun is a gen 1 Impact with some upgrades.

I weighed more pellets, and am amazed at the spread.

Lightest was 32.6 with heaviest at 34.9. that's nearly 7% of the advertised 33.95 weight. Only one each of the 32.6 and 34.9, but plenty in between.

Now that I have a bunch sorted, I'll chrony a test batch later this week (I hope, all depends on time).

Smart-test it for yourself. Then you will actually know.

Saltlake58

Hammer is maxed. Absolutely no play in the hammer spring. The gun is a gen 1 Impact with some upgrades.

I weighed more pellets, and am amazed at the spread.

Lightest was 32.6 with heaviest at 34.9. that's nearly 7% of the advertised 33.95 weight. Only one each of the 32.6 and 34.9, but plenty in between.

Now that I have a bunch sorted, I'll chrony a test batch later this week (I hope, all depends on time).

Smart-test it for yourself. Then you will actually know.

July 26, 2021 at 11:59 am Link

Saltlake58
Participant

Member
United States
Accuracy: +64

thomasair

If you can’t raise the hammer….then lower the reg pressure.

Mike

I went through the normal Impact tuning procedure where I start at about 90 bar, and the hammer spring not maxed out. then increase the reg pressure till the speed drops, then bring hammer spring up to overcome the reg pressure on the valve. I settled on about 110 bar and maxed out hammer spring. That allows me to shoot the 3395 heavies about 830 or 840. That seemed like a broad spread, so I thought what else could effect muzzle velocity, which is where pellet weight came from. I plan on testing the lightest to heaviest sometime this week to see if shooting a single weight (to the tenth of a grain) tightens up the FPS spread.

Gun is a gen 1 Impact with a Power Plenum and X Barrel installed. Once I shoot the various weights, I should have a better idea of the impact pellet weight has.

thomasair

If you can’t raise the hammer….then lower the reg pressure.

Mike

I went through the normal Impact tuning procedure where I start at about 90 bar, and the hammer spring not maxed out. then increase the reg pressure till the speed drops, then bring hammer spring up to overcome the reg pressure on the valve. I settled on about 110 bar and maxed out hammer spring. That allows me to shoot the 3395 heavies about 830 or 840. That seemed like a broad spread, so I thought what else could effect muzzle velocity, which is where pellet weight came from. I plan on testing the lightest to heaviest sometime this week to see if shooting a single weight (to the tenth of a grain) tightens up the FPS spread.

Gun is a gen 1 Impact with a Power Plenum and X Barrel installed. Once I shoot the various weights, I should have a better idea of the impact pellet weight has.

July 26, 2021 at 9:39 pm Link
Saltlake58
Participant

Member
United States
Accuracy: +64
Well, I shot a couple strings tonight. The string that really stood out was finding a batch of pellets that are within 1/10 of a grain.

String 1:

25 caliber Impact Gen 1

Pellets all weigh 33.90 to 33.99 grains. No other changes were made from last string a few days ago. Spread dropped from 28 fps to 11 fps just by weighing and selecting same weight pellets.
```
Shot count: 10
Low: 826
Hi: 837
Avg: 831
STD Dev: 3.4
Spread: 11.0

7/26/21 7:05:10 PM,828
7/26/21 7:05:24 PM,833
7/26/21 7:05:28 PM,830
7/26/21 7:05:32 PM,835
7/26/21 7:05:36 PM,828
7/26/21 7:05:39 PM,833
7/26/21 7:05:42 PM,828
7/26/21 7:05:45 PM,830
7/26/21 7:05:47 PM,837
7/26/21 7:05:52 PM,826
```
I guess that means for high accuracy shooting, I'll be weighing. It seems to work.
Well, I shot a couple strings tonight. The string that really stood out was finding a batch of pellets that are within 1/10 of a grain.

String 1:

25 caliber Impact Gen 1

Pellets all weigh 33.90 to 33.99 grains. No other changes were made from last string a few days ago. Spread dropped from 28 fps to 11 fps just by weighing and selecting same weight pellets.
```
Shot count: 10
Low: 826
Hi: 837
Avg: 831
STD Dev: 3.4
Spread: 11.0

7/26/21 7:05:10 PM,828
7/26/21 7:05:24 PM,833
7/26/21 7:05:28 PM,830
7/26/21 7:05:32 PM,835
7/26/21 7:05:36 PM,828
7/26/21 7:05:39 PM,833
7/26/21 7:05:42 PM,828
7/26/21 7:05:45 PM,830
7/26/21 7:05:47 PM,837
7/26/21 7:05:52 PM,826
```
I guess that means for high accuracy shooting, I'll be weighing. It seems to work.
July 27, 2021 at 9:25 am Link

egd
Participant

Member
United States
Accuracy: +2

Your chrony numbers were more consistent, but were those any more accurate?

July 27, 2021 at 9:15 pm Link

Saltlake58
Participant

Member
United States
Accuracy: +64

Haven't gone to the range yet to test latest modifications. Those are just chrony numbers, but my experience is that more consistent speeds = removing one random element that effects my shooting.

Just finished another set of tests to see how much 1 grain difference in weight makes, and it's about 20 fps. with luck, I'll be able to get to the range next week. Oh, how I'm looking forward to retirement

Haven't gone to the range yet to test latest modifications. Those are just chrony numbers, but my experience is that more consistent speeds = removing one random element that effects my shooting.

Just finished another set of tests to see how much 1 grain difference in weight makes, and it's about 20 fps. with luck, I'll be able to get to the range next week. Oh, how I'm looking forward to retirement

July 27, 2021 at 9:54 pm Link

Centercut
Participant

Member
United States
Accuracy: +185

I think maybe shooting just 25M or 50Y it may be debatable. But 20 FPS at 100Y is the difference between winning and losing. I’ll be weighing and inspecting my .22 RD Monsters prior to RMAC and EBR. I’ve been burned by damaged or inconsistent pellets in competition at 100Y before. Not going to happen again. 😉

July 27, 2021 at 10:03 pm Link

Saltlake58
Participant

Member
United States
Accuracy: +64

Centercut – typically I shoot at 75 yards (lane limit at the range I shoot at.) they have a 100 yard range, but I prefer the 75 for ease of target setting. However, my goal is to shoot consistently at 100. That's why I'm putting in the effort to work consistency into the gun so if I miss, I know it's me and there are no excuses. Besides, I'm a control freak and having absolutely consistent shots is kind of the holy grail of shooting.

I probably won't be at RMAC this year (work is a pain, as you probably know), but someday!

Every one enjoy!

Centercut - typically I shoot at 75 yards (lane limit at the range I shoot at.) they have a 100 yard range, but I prefer the 75 for ease of target setting. However, my goal is to shoot consistently at 100. That's why I'm putting in the effort to work consistency into the gun so if I miss, I know it's me and there are no excuses. Besides, I'm a control freak and having absolutely consistent shots is kind of the holy grail of shooting.

I probably won't be at RMAC this year (work is a pain, as you probably know), but someday!

Every one enjoy!

July 28, 2021 at 1:29 am Link

Xbowsniper
Participant

Member
United States
Accuracy: +37

Nation,

As many of you know, I shoot Field Target competitively. I've sorted pellets by weighing, checking head size, resizing, rolling, and inspecting the domes.

My general go to projectile has been either a JSB, or Air Arms 8.44.

I've chronograph an entire tin of JSB'S in the past, and found a 53 FPS difference between the highest and lowest within the tin.

I've also weighed an entire tin. What I found, was absolutely atrocious. I found pellets that weighed anywhere between 8.08 grains, on up to 8.74 grains. I also found that only about 40 pellets in the tin actually weighed 8.44 grains.

I've done the same with Air Arms as well. The FPS spread was considerably less at around 35 FPS or so. The tolerance of the Air Arms pellets was closer as well, with the lightest pellet weighing 8.22 grains, and the heaviest weighing 8.66 grains.

I did not do tests on either for accuracy, or lack thereof.

What a can attest to, is, before sorting, I would get 5-6 "mystery " shots in a 60-72 shot match. Once I sorted by weighing them, I'd get maybe 3-4. After going through all of the culling methods I mentioned above, I'll get 1 or 2 in the course of 2 matches combined. I'll always sort using all of my above methods for a Grand Prix match, or Nationals. I don't usually do that for local matches, and some of my scores definitely reflect that.

Tom Holland

Field Target Tech

Fieldtargettech.com

Nation,

As many of you know, I shoot Field Target competitively. I've sorted pellets by weighing, checking head size, resizing, rolling, and inspecting the domes.

My general go to projectile has been either a JSB, or Air Arms 8.44.

I've chronograph an entire tin of JSB'S in the past, and found a 53 FPS difference between the highest and lowest within the tin.

I've also weighed an entire tin. What I found, was absolutely atrocious. I found pellets that weighed anywhere between 8.08 grains, on up to 8.74 grains. I also found that only about 40 pellets in the tin actually weighed 8.44 grains.

I've done the same with Air Arms as well. The FPS spread was considerably less at around 35 FPS or so. The tolerance of the Air Arms pellets was closer as well, with the lightest pellet weighing 8.22 grains, and the heaviest weighing 8.66 grains.

I did not do tests on either for accuracy, or lack thereof.

What a can attest to, is, before sorting, I would get 5-6 "mystery " shots in a 60-72 shot match. Once I sorted by weighing them, I'd get maybe 3-4. After going through all of the culling methods I mentioned above, I'll get 1 or 2 in the course of 2 matches combined. I'll always sort using all of my above methods for a Grand Prix match, or Nationals. I don't usually do that for local matches, and some of my scores definitely reflect that.

Tom Holland

Field Target Tech

Fieldtargettech.com
Author

Viewing 20 posts - 1 through 20 (of 22 total)

1 2 ›

You must be logged in to reply to this topic.