WEIGHING VS. RIM THICKNESS - part 2 100 yards

[TOP PREDATOR]

I started off at 50 yards, see: WEIGHING VS. RIM THICKNESS - part 1, 50 yards . Unfortuanately we've been plagued with enough wind that would not do a 100 yard test justice, and today was the first chance I had to hit the range in a calmer setting.

Just as in the 50 yard test, three different ammos were shot from a Savage MKII BV 20" heavy barrel, bipod and rear bag, 1 lb trigger, 18x on the scope. 65 deg., high humidity (80%), cloudy to partly sunny, 3-5 mph but managable wind (may have opened up groups slightly).

I seperated the ammo like in the 50 yard test - several different 5 round same weight lots, several 5 round rim thickness lots (making sure that every round weighed differently to ensure results were based on rim thickness, not weight). This time I brought the chronograph to measure what is any differences / simularities there were between the diffeerent weight and rim thickness lots of the three different ammos, placed 5 feet from muzzle. Groups were measured on the outside edges of the group.

Group #1 excluded obvious flyers (main body of the group), group #2 included obvious flyers (ranging .25" to 1.25" away from the main group). Anything further away I considered a pulled shot and took another round to replace it. Any shot that I knew I pulled was refired also.

AGUILA MATCH RIFLE

(weight sort):

Weight - avg. fps - dev. - grp. 1 - grp. 2 - # flyers

50.6 gr --- 1001 --- 42 ---- 2.5" ----- 3" ------- 1
50.8 gr --- 1010 --- 20 ----- 1" ------ 1" ------- 0
51.0 gr --- 1017 --- 7 ----- 1.5" ----- 2" ------- 1

(rim thickness sort)

Rim t. - avg. fps - dev. - grp. 1 - grp. 2 - # flyers

.0355 ---- 1008 --- 25 ---- 1.5" ---- 2.25" ----- 1
.0360 ---- 1010 --- 14 ---- 1" ----- -2.75" ------ 2
.0365 ---- 1020 --- 13 ---- 1.75" --- 2.5" ------ 2
.0370 ---- 1011 --- 31 ---- 1.25" --- 2.25" ----- 1
.0375 ---- 1014 --- 30 ---- 1.5" --- -2.25" ----- 1

FEDERAL BULK PACK

(weight sort)

Weight - avg. fps - dev. - grp. 1 - grp. 2 - # flyers

49.1 gr --- 1143 ---- 61 ----- 2" ----- 3.25" ---- 1
49.2 gr --- 1163 ---- 49 ----- 2" ------- 3" ------ 2
49.3 gr --- 1165 ---- 57 ----- +2" ----- 2.5" ---- 1
49.4 gr --- 1199 ---- 42 ----- too large to mention / measure accurately

(rim thickness sort)

Rim t. - avg. fps - dev. - grp. 1 - grp. 2 - # flyers

.0350 ----- 1193 --- 56 --- 3.25" --- 3.25" ---- 0
.0355 ----- 1157 --- 68 ---- 1.5" ---- 3.5" ----- 2
.0360 ----- 1177 --- 40 ----- 2" ----- 3.5" ----- 2
.0370 ----- 1175 --- 51 --- 3.25" ---- 3.5" ---- 0

CCI BLAZER

(weight sort)

Weight - avg. fps - dev. - grp. 1 - grp. 2 - # flyers

50.5 gr --- 1230 ---- 50 ---- 1.25" --- 2" ----- 2
50.7 gr --- 1237 ---- 35 ----- 1.5" -- 1.75" --- 1
50.9 gr --- 1238 ---- 38 ----- +2" --- 3.25" --- 1
51.2 gr --- 1246 ---- 19 ----- 1.5" -- 1.5" ---- 0

(rim thickness sort)

Rim t. - avg. fps - dev. - grp. 1 - grp. 2 - # flyers

.0380 ----- 1239 --- 12 --- +1.25" --- 2" ------ 1
.0385 ----- 1233 --- 30 ----- 2" ---- 2.25" ---- 1
.0390 ----- 1243 --- 35 ----- 1" ---- +1" ------ 0
.0395 ----- 1238 --- 22 ---- 1.5" --- 2.25" ---- 1

The one trend I did notice with all three ammos (in general) is that with the weight sort the FPS increased and deviation between the highest and lowest FPS decreased as the lots used heavier ammo. No such trend was evident with the rim thickness sort.

Both weight sorting and rim thickness sorting improved on the baseline groups shot by .25" to 1" - the baseline groups were 5 shots each of different weights and rim thicknesses to guage what or if any improvement was made. I also felt this simulated an absolute randomly picked "out of the box" 5 shot group.

CONCLUSIONS:

weight sorting -

1. Tighter groups, however flyers were further away from the main group.
2. The heavier the weight the higher the FPS.
3. The heavier the weight the lower the deviation.
4. More predictable the group and velocity.


rim thickness -

1. Larger groups, most flyers were not so far away from the main group.
2. No real trend or correlation between rim thickness and change in FPS or deviation.

Weight sorting produces more "lots" than rim thickness, perhaps telling me that it singles out more differences than rim thickness sorting. Although neither completely weeded out flyers, both did work to reduce them drastically and shrunk group size. Most of what I call "flyers" were only .25" away from the main group. If you feel that a .25" or even a .5" impact away from the main body of the group isn't really a flyer, you can make adjustments to the above measurements and eliminating many "flyers".

Both weight and rim thickness sorting produced a "magic lot" or two in all three ammos that the rifle really liked and produced a better group than the other lots. By looking at the group's size and shape, it appears that the rim thickness sorting was less "finicky" when switching from one lot to another, perhaps due to the larger group size as compared to weight sorting at 100 yards.

Strangely enough, the group results of 100 yards almost completely contridicts the 50 yard results. At 50 yards rim thickness seemed to have and advantage, while at 100 yards weight sorting performed better. The only thing i could ASSUME is that at longer distances, whatever it is about weight sorting superceeds rim thickness sorting and takes priority at those longer distances. If I didn't shoot it myself, I probably wouldn't believe it either. Yet another rimfire mystery.

For me, it appears that at shorter distances, rim thickness wins for group size, and for longer distances weight sorting. Of course different ammos, rifles, etc. may have different results. However, the use of the chronograph revealed the better consistancy of the weight sorting over the rim thickness sorting and the groups at 100 yards backed it up on average. This consistancy with the weight sorting in the end equates to accuraccy, at least at further distances.

Isn't that what it's all about?

 

[DUCKSHOT]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

Thanks for the info TP. I guess know I'll have to get something to measure weight. I'm tryin to get out to 100 yd and beyond accurately.

 

[Greg Langelius *]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

So TP;

Is all this sorting 'worth it' <span style="font-style: italic">for the average shooter doing training</span>?

Greg

 

[HathcockProtege]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

Correct me if I'm wrong, but it would seem to me that one could see a big improvement and decrease in flyers simply by sorting out the extreme high and low measurements based on both methods of sorting for all ammo.

Thanks for the write up.

-The Kid.

 

[Stringer]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

Great experiment and report! Thank you

 

[TOP PREDATOR]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">So TP;
Is all this sorting 'worth it' <span style="font-style: italic">for the average shooter doing training</span>?
Greg</div></div>

i would think that for someone that's shooting at an aluminum can 25yards away to basically make dust with a semi - not so much. for the average joe that's satisfied with 3" groups at 50 yards - not so much.

for folks that don't have enough $ to spend on eley, wolf, etc. and like to shoot alot and accurately and have a little time on their hands, yes i think so. plus i believe that it is one way for an average shooter to become a better than average shooter, as most average shooters wouldn't bother doing it in the first place.

i thought of and was suggested to me to do rimthickness and weight sort. i tried it with a couple hundred rounds, it takes way too much time. in that case might as well buy the good stuff, and spend the extra time working a part time job to pay for it.

i have 2,000 rounds that just showed up at my door, i'll time how long it takes to weigh them out. does it turn not-so-match ammo into match ammo? no, but it does make an improvement out of not-so-good ammo enough that i think it's worth it. along with lubing them if no lube is present, squeezes performance (or at least consistancy) of a 20.00 brick ammo rivaling 30.00 to 35.00 brick stuff. sorting 30.00 to 35.00 a brick stuff to much higher stuff performing stuff. i'd love to buy wolf exclusively, and i was for a while, but i found that i do too much shooting to afford that.

let me rephrase that - it doesn't make the ammo perform better, just groups them into more consistant lots, which shows up better on paper with better groups, which in turn allows a better range experience, and training as most of the time you can blame yourself for a blown shot, and not chalk it up to having too many flyers in the ammo.

if you had told me 6 or 7 years ago that i'd be shooting a .22 at 200 yards (on purpose)and getting -7" ish groups i'd say you were crazy. this is one of the ways i've found to make the bulk of groups -5" at 200 yards.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HathcockWannebe</div><div class="ubbcode-body">Correct me if I'm wrong, but it would seem to me that one could see a big improvement and decrease in flyers simply by sorting out the extreme high and low measurements based on both methods of sorting for all ammo.
-The Kid.</div></div>

when i started getting more into the rimfires and sorting, i had to set a baseline with my first few bricks, what worked the best and not so much, and then finding the magic lots in each that worked well.

i know out of the ammo i just got that there are 4 weight lots to "save" that are just right for paper competition, a few that i can get by with, a few for "burning up" for practice or smallbore silhouette, and the rest for sighters / foulers. those lots are more towards the higher extreme weights of the whole bunch.

if i went to an ammo i never shot before, there's a good chance that the the extreme high or extreme low measured lots is the magic lot that groups the best out of them all.

 

[Tuna921]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

I think ignition is key and rim thickness is important. If you have light and heavy strikes on the primer the bullet will do different things.if you have consistant strikes the bullet flight should be the same. Does it weight more or less because of thinkness of the rim, lead or coating ? If you don't have consistant primers strikes nothing will shoot well....Jim

To quote Bill Calfee

The only two things about an accurate rimfire rifle, that change every time you pull the trigger, are the "bullets" and the "IGNITION"......

If you have "killer" ignition, and "killer bullets" you can win.....

If you don't, you can't draw a smell....

I can't do nothing about the bullets, but I sure can about the ignition.

What would be interesting would be a sort by rim thickness and then by weight .You will first find the thickness your rifle likes then the speed . You might then have your ammo sorted to shoot scores and the other to practice

 

[clmayfield]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

Calfee is a great rimfire smith with some interesting theories, some of which hold water and some don't. His insistence on firing pin striking at 6 o'clock has long been disproven, for instance, yet he clings to the belief so firmly that he doesn't believe in barrel indexing, which has proven effective.

Many believe that sorting by rim thickness works because a 22LR headspaces off of the rim. Change the rim thickness, and you change the headspace. I don't know if there is any way to prove this.

Isn't the bullet the heaviest part of a 22lr cartridge? Sorting by weight, you are likely sorting primarily by bullet weight.

 

[TOP PREDATOR]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

although it makes sense that the thicker the rim, the more the casing and primer element, the higher the weight.

oddly enough, i found no concrete evidence that the thickness of the rim adds enough weight to make a difference. most of the same rim thickness lots included many different weighted rounds in them. there was no correlation that the thicker the rim, the higher the average weight within that particular rim thickness lot.

on the primer strikes - i did read an article somewhere (written by someone that's a hell of alot more anal than i) that a heavier primer strike causes the powder in the casing to move forward more than a softer strike, causing the powder to burn at a more inconsistant rate between being stuck hard or soft.

supposedly by lowering or lifting the muzzle before shooting puts the powder to the back or the front of the casing more evenly, causing a more uniform ignition. sounds feasible, but way too technical for me to even think about analizing or is my equipment that presice. but maybe not, i'll give it a whirl and if there's an "eureka!" moment, i'll post 'er up.

true, i'd think that unless you took every cartridge apart and weighed every component, there's no way of telling why one weighs differently than the other. of course it would be impractical, if not impossible to do that. and even though weight sorting or rim thickness didn't remove all flyers, both went a long way on average to improve group size and reduce the amount of flyers.

why does it work? many reasons many theories, no 100% definite answers. it just seems to work.

 

[Tuna921]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body">

Isn't the bullet the heaviest part of a 22lr cartridge? Sorting by weight, you are likely sorting primarily by bullet weight. </div></div>

Most rimfire smith's set there firing pin strike depth for the ammo your using which I would imagine is ELEY.They want a fast clean strike doesn't have to be deep just enough.I dont think the total weight means much with that litte of a variance at 100 yards the wind is what matters.A 1 or 2 MPH wind change can throw a shot way off or no wind change can hold a group tight. Think of it this way if you have a primer on a centerfire seated at different depths what will happen ?

TP, yes it did work for you and great results and time to post it. Rimefire can be frustrating and hard to find the answers but we all keep trying. It's fun

Jim

 

[clmayfield]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

Rimfire is a crazy sport. I knew a guy who was holding over because he was afraid that the way his scope was dialed in, the harmonics of the gun were tuned just right. There is a lot of witchcraft in the sport. I think the natural variability of the beast forces superstition to make people believe that they can control something they can't.

Still... a great sport, nonetheless.

 

[kirkhamg]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

I have been messing around with the weight/lube/rim thickness thing as well. Last week I took some (50)Remington Sub-sonic that had been previously weight sorted, and sorted them into two lots based on rim thickness. I shot 30 rounds that were of the same weight and rim thickness. Five warm-up/sighting shots and then 25 rounds at the TQ4 target. I know I am not the best shot, but for the last few months I have posted a 240/250 in the monthly match, using a few different entry-level match ammo selections. My score was on track with a 239/250. The most notable finding was one glaring hole in the target that located deep into the 8 ring. It was definitely ammo related as I had noted all shots that broke poorly i.e. heart-beat, breathing, jerked trigger, etc. and they were all comfortably in the 9 or caught the edge of the 10.

I spent a bunch of time and effort last summer with other brands as well. I have found that if you are going to mess around with cheap ammo, then weight sorting will:
(1) cut average group size - but maybe not enough
(2) reduce the number of "flyers" - but not eliminate them
(3) not show consistent performance at different distances
(4) most significant improvement for the least effort is achieved when starting with a good lot, and "culling" the few high and low weights; and just shooting the rest.

I thought I would never pay center-fire prices for rim-fire ammo, but these things are addictive. I hope to try a box of Eley for the 200 yard match (May)

 

[Greg Langelius *]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

Thanks; I appreciate the well considered reply.

 

[TOP PREDATOR]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TOP PREDATOR</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">So TP;
Is all this sorting 'worth it' <span style="font-style: italic">for the average shooter doing training</span>?
Greg</div></div>


i have 2,000 rounds that just showed up at my door, i'll time how long it takes to weigh them out.
</div></div>

500 rounds, took 1.5 hours to weigh out, probably about 15 minutes more if just just beginning with a new or different ammo, to see what the "parameters" (lowest to highest lots) are.

 

[Inline6]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

FWIW I keep my lots separated in .2 of a grain i.e. 0-.2, .3-.4, .5-.6 ect. It has worked well for me. All I shoot is SK rifle match, with that said I wonder what your results would have been with higher quality ammo? I under stand what you are trying to achieve, good write up.

 

[TOP PREDATOR]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

i did it with the sk, and wolf also, scary good accurate alone, the sorting seemed t make it even better.

 

[jr81452]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TOP PREDATOR</div><div class="ubbcode-body">although it makes sense that the thicker the rim, the more the casing and primer element, the higher the weight.

oddly enough, i found no concrete evidence that the thickness of the rim adds enough weight to make a difference. most of the same rim thickness lots included many different weighted rounds in them. there was no correlation that the thicker the rim, the higher the average weight within that particular rim thickness lot.
</div></div>

All the shells are made from the same lot of brass blanks, thus they all weigh within the blank manufacturers tolerances. A thicker rim would be more likely to indicate thinner cartridge walls or shorter case length than more weight.

 

[Rthur]

Re: WEIGHING VS. RIM THICKNESS - part 2 100 yards

fwiw I think it has decreased my vertical stringing by half from non sorted ammo. btw I also sort mine to the tenth of a grain R