Waltz, DRock, PacoAcu’Rzr resizing dies bulk 22LR testing


In early 2010 7 experienced shooting buddies and I began to discuss the merits of resizing .22 non magnum rimfire rounds.

We are all retired with decades of experience in a variety of formal shooting disciplines, bullet casting and handloading.  My bullet casting etc. started in 1967.

A major reason for doing this testing was what information there was on a variety of sites was anecdotal in nature which basically means that the conclusions were either based on casual observations or indications rather than rigorous or scientific analysis.

We wanted an in depth controlled analysis as rigorous as we could afford over a fairly decent product data base.

What follows is the best that we could do.


While .22 rimfire rounds are forged from lead wire they are essentially the same as a cast bullet.

A fundamental requirement in bullet casting is to create a bullet where the driving bands are the best match to the throat/chamber/forcing cone, whatever you choose to call it, as possible for that particular weapon and that particular ammunition.  You create that match by using sizing dies after the bullets are made.

Driving bands look like so.


The bullet on the left is as from the mold, the center is with a gas check applied and in many cases is
not required depending on a variety of factors, and the bullet on the right is sized and the driving bands
are lubed.
On a .22 non-magnum rimfire they simply are the bands above the top of case or:

22 BULLET DIAMETERS only the pic

Since the resizing dies not only create a variety of nose shapes but also resize the driving bands it stood
to reason that using them to create not only a more effective hunting round but also a more accurate
round whether used for hunting or not could be expected and because of that we decided to test them
under the most controlled conditions that we could manage.
I have my own ranges where I can shoot from either inside or outside at will, using solid benches
and/or off the ground. They are 100 yards and 650 yards long. The 100 yard range is surrounded by
oak and pine trees which create a natural wind barrier and faces North to South. The outside benches
are covered so that sun on the sights is not an issue. This was the range we used for the tests.
We also own 86 acres of forested and pastured land containing a fair sized pond with lots of small game
that we can hunt.
We had access to and used sophisticated measuring tools from a factory I ran which included laser
measuring and electronic weighing instruments.

While I published the protocols and results over the testing period which lasted over 7 months on Rimfire Central, I have been asked to kind of create a summary of them in a single document which I am attempting to do here.

The purpose of the document is not to solicit differences of opinions nor create debatable positions albeit also not to discourage either, but simply to document the protocols etc. and go over them with why we chose them and the results.

There is no “absolute” way to do something like this since it is as much an art as a science and again was simply our way.

The sizing die sets as well as the ammo used in the testing were all purchased by us and we have no connection whatsoever with the folks that make and of them.

What follows indicates actual test results along with “In Our Opinion” (IOO) and “In Our Experience” (IOE) subjective comments.


A number of the weapons are not MOA capable at the ranges tested.

I cannot emphasize that enough!


Our first step was to determine what we wanted to test.

We decided on testing only stock weapons as they came from the factory. No alterations. No trigger jobs, no bedding, no stock replacements, no after market barrels, no re-crowning, no target jobs etc. Scopes were OK.

Had to be NON TARGET weapons that a “normal” shooter could purchase in a variety of places. We selected 20 weapons, both rifle and pistol with no two weapons duplicated relative to brand/model.

The weapons had to be “seasoned” which to us meant having at least 1,000 rounds through them. In our opinion (IOO) and experience (IOE) .22 non magnum rimfire weapons don’t reach their accuracy potential until they are shot quite a bit and 1,000 rounds, while an arbitrary number, showed through the years that after that, measurable increases in accuracy generally do not occur often.

We decided to use bulk ammo, no target stuff etc. and again what a normal shooter could expect to find. The bulk price had to be =<$24 per brick tax included.

We chose the largest selling brands from our local Bass Pro Shop where one of our testers was the manager. They were Remington Golden Bullets, Federal 550 bulk, Winchester XPRT 36 gr HP, Winchester Wildcats and Remington Thunderbolts. We had some trouble with the GB’s with cases splitting so we replaced them with Federal Lightnings about 1/3rd of the way through. We paid for all the rounds.

We decided that the range(s) would be 100 yards for rifles with one exception and 50 yards for pistols regardless of sights. IOO and IOE this gave the easiest variation measurement rather then at 25 or 50 for rifles and 25 for pistols and those were the ranges we trained at when we started to learn how to shoot. Again “oooh/aaah” groups were not the goal!

We decided that 3 5 round groups after “re-lubing” for the unsized rounds would be shot for record and within a total time limit of 30 minutes. 2 minutes per string, 5 minutes minimum between strings. Ditto for the sized rounds.

From a practical standpoint one complete successful session with one firearm averaged about 90 minutes.

Any variation from those time limits which included significant atmospheric changes, latrine breaks longer than 10 minutes (we are all “well-seasoned” shooters), eye strain or the “palsy” because of our age would result in any strings shot up to that point being quarantined and all the sets had to be shot over.

It was extremely important to us the all the testing for a set was done under the same conditions. A “set” being defined as all the required groups for unsized as well as sized for a particular ammo/brand and a particular weapon.

Ditto if the testing just started to become a job instead of fun which happened some near the end of the 7 months which is a long time to do a project like this.

If we shot say (3) 5 round unsized sets for all 5 the ammo brands and then (3) 5 round sized sets for only 4 of the 5 ammo brands and it started to rain or the shooter just simply lost interest, any or all of the above, then all of those “sets” were quarantined and we were back to square 1.

We decided 1 alibi round per ammo brand per string was allowed with the condition that the shot had to be called by the shooter at the shot and before it was checked using the spotting scope. If not then wherever it landed was counted as part of the group. Ditto if it was called wrong.

We decided that all 5 ammo brands had to be fired on the same target so we had to design a method to easily see the results. This is an example on how we did that.


We used .25” folder dots from Walley World to mark the bullet holes as indicated on the targets above.

The grid size is 1”x1” on all the targets.

The results on the target on the left is for unsized rounds and for the target on the right is with resized rounds.

We used this target stand.



The design allows it to be placed anywhere and the backer can be easily removed and replaced which comes in handy if you don’t want to bend down all the time. You simply lift it off the bent metal “holders”.

Portable, inexpensive and easy to make, folds down for carrying and transportation and the spread of the legs can be adjusted to any reasonable width which also adjusts the height of the target.

You can see one of our sophisticated wind flags taped on the stand.

Our process was to tape the target(s) on the backer board, shoot a set, lift the the backer board off the stand so it could easily be messed with and then remove the target. Masking tape was then put on the back of the target over the bullet holes just created.

Then taking the appropriate folder dot, it was placed on the front of the target over the bullet holes. Between the glue on the folder dot and the glue on the masking tape the dots were firmly anchored to the paper.

We decided that “custom” targets were needed which in a number of cases were not bulls-eyes The reason for that was that many people fire better groups with non bullseye targets then with them. I am one.

This is the results of the Waltz die set for the weapon indicated.


Guy that owns the rifle hunts rates with his grandson at a closed dump with a maximum range of 75 yards so for that rifle we did not test at 100 and made the “rat” target for them.

We decided that the weapon had to be thoroughly cleaned and only “re-lubed” between ammo brands. 10 minutes for that process was the goal.

We decided what radio station would be on the radio via the good old “short straw” method.

We decided that when BAMA football was on the tube no testing would be done.

We decided, actually they did, that I would supply the soft drinks.

The above process took us almost longer then the testing. If you can imagine a whole bunch of old
farts debating stuff like the above you can understand why.

The first step was to determine how many rounds needed to be fired between ammo brands in order to “re-lube” the bore and the cleaning method(s).

We, actually me, contacted 5 ammo manufacturers and got to the engineers that actually do the accuracy etc. testing and asked them about cleaning and re-lubing and the following are OUR procedures based on those phone calls.

Cleaning was a couple of wet patches soaked in Mineral Spirits between ammo brands followed by dry patches until bore was dry. The MS removed all the lube which is only what we wanted to be removed.

The people we contacted went from 1 saying only 3 lubing shots were needed after cleaning and the other 4 saying 7-10. We went with 10 and used the appropriate unsized bullets to re-lube the bore.

So the protocol was to clean before each brand of ammo and fire 10 shots to re-lube before shooting groups for record.


We weighed and measured cartridge length, driving band diameters and Brinell hardness for the bullets using random samples from each brick, normally 50.

Mean Absolute Deviations (MAD) on overall cartridge length averaged around +-.5% against an overall average length (OAL) set of measurements for each ammo/brand/type.

Mean Absolute Deviations (MAD) on driving bands ran from +-2.8% for the Remington Golden Bullets to +-8.3% for the Federal 550 bulk against a SAAMI standard of .224” with the lube cleaned off first.

The differences in bullet hardness ranged from 5.0 which is what they should be since the bullets are supposed to be pure lead to 5.11 for the Winchester XPRT 36 gr HP’s. Some Thunderbolts were even higher but not enough to form any patterns.

We also tested concentricity for awhile but determined it was a waste of time since the tool(s) are designed to measure unlubed jacketed bullets being concentric to the base of the cartridge or to some portion of the case.

Since .22 non magnum lead bullets do not align via the nose but rather the driving bands the tool(s) are fundamentally worthless.

We discussed this with a number of Olympic shooters and their comments fundamentally came out that the tool(s) for that were nothing more then expensive paper weights. Also discussed with a RFC member who has published a number of “shooting” articles.

We made a test bed on a jewelers lathe to test concentricity.

We actually took a number of cartridges and bent the bullet out of alignment. We could not discern any extra ordinary negative results on group sizes which was to be expected because the bullet will “re center” itself when chambered. Any negative variations were well within shooter performance or lack of it.

We also tried to discuss this with the Nielson Brothers who make and aggressively market a $300 tool to test concentricity but after a few pertinent questions they no longer answered our calls or responded to our emails.

Finally we tested “loose” bullets against “tight” bullets. Again any negative variations were well within shooter performance or lack of it.


There were some opinions that when resized that a “tighter” case on the bullet heel would help in accuracy. Real issues with that as there are no dimensional drawings, at least that we could find, as to the diameter of the heel and trying to get a bunch of bullets out of the cases without darn near destroying them is about impossible. Folks we talked to all pretty said the size and shape of the heel was proprietary so they were no help.

On the few that we did get out without mashing the snot out of em the diameter of the heel was even smaller then the ogive of the bullet directly in front of the driving bands.

IOO the fact that the heel is hollow based and even when we really squashed some of the “loose” rounds down they still were loose, leads us to believe that expansion to throat size is not as important as the driving bands cause they are already creating a gas seal.

Based on a number of independent tests over the years the form of the base of the bullet is more important then the form of the nose of the bullet. IOO the consistency of expansion of the hollow based heel was more important to accuracy then the whether or not the heel formed a gas check or not.

Falling back on our bullet casting experience but the best we could come up with.


Then the actual testing started.

We purchased 2 die sets each for the Waltz, DRock and Paco Acu’Rzr (Patent Pending).

One set was to be used to determine if there was a practical way to set off a round during use. We could not set one off and the final test was to load in a round in each die, put the die in a pipe with the base of the die on a steel plate and stick a fitted solid rod into the other end of the pipe.

A 20 pound weight was then dropped on the end of the solid rod thus applying a huge amount of force to the bottom of the die, the loaded round and the metal plate.

The only things that happened were that the dies were destroyed and jammed into the pipe to the point they had to be cut out to look at them. Urinated away a fair amount of money on that testing.

While there are folks running around that can break an anvil IOO and IOE you would have to specifically design a tool to set a round off using any of the dies. IOO and IOE you probably have a higher chance setting of a primer during seating in hand loading then a round with any of the dies.

We then used the dies to resize 50-150 rounds for each of the ammo/brands. Single resizing for the Waltz and DRock and 6 different diameters for the Acu’Rzr since we bought the extra “over-sized bore” dies.

Any left over rounds were stored in empty medicine bottles…we got lots of those….and labeled.

Since there is a perception that using a mechanical press and a depth limiter vs “tapping” to resize the round we made a depth limiter for the PacoAcu’Rzr. Looked like so.


We started with ammo brand “A” and set up the appropriate number of targets including the “extra” ones for the PacoAcu’rzr. A 5 round group on each target was fired. On the first set of targets the ammo was unsized and on the following sets the ammo was resized.

In the event of an alibi round it was marked as “called” and not included in the group size. See the left groundhog target above with the Federal 550, yellow dot, with that notation as an example.

Same protocol for brand “B” etc. until all the brands had been shot.

If during the test cycle any of the following happened then all the results shot up to that point were quarantined and not considered in the final evaluation(s).

Atmospheric conditions changed or were present to the point that we decided they would alter the results. Wind went up to over 5 MPH or changed direction dramatically. Remember the 100 yard range is sheltered.

Could shoot in the cold from inside of the shed as I can heat it with a turbo kerosene heater but can’t cool it unless I was Bill Gates.

If temperatures outside were over 85F we did not shoot. With the humidity here in Alabama +85F can be uncomfortable.

Clouds rolled in that affected the ability to see the target relative to the previous group shooting.

Started to rain.

Etc. relative to atmospheric condition changes.

Time constraints were not made due to a variety of reasons.

Latrine breaks which effected the time constraints. At our age when you gotta go you gotta go.

Vision issues such as vision going blurry from the concentration on the target/sights etc.

The advent of “palsy” which made the gun wobble beyond what would normally experienced.

“Spirited” discussions about a group etc.

Jams or other mechanical issues. Did not have any of those but if so and correcting them resulted in failing the time constraints the testing for that ammo/brand/weapon had to be started all over.

There were enough of the above affecting the testing that we quarantined about 60% of the groups and had to do them over from the beginning.

AGAIN….It was extremely important to us the all the testing for a “set” was done under the same conditions.

What follows are our findings and conclusions.

First of all, all the tools are of excellent quality and robust unless you abuse them.

If you are gonna mess with this stuff you need a Micrometer to measure. A dial caliper is simply not accurate enough and getting them to repeat is iffy and a PIA.

We were skeptical that using a depth limiter was the most effective way. That tool or protocol is used to seat a bullet prior to crimping etc. Using it in a resizing protocol in a mechanical press or even in a “tapping” type tool like the PacoAcu’Rzr for bullets already seated and crimped and there is a HUGE difference in seating and messing with bullets already seated, can result in the bullets being seated too deeply with either some shaving of the lead off the case or a thin coating of such around the crimp.

All you need to do is set the die(s) using the shortest OAL and because of the lack of “feel” with a mechanical press etc. or even tapping, it is very easy to “shave” the bottom of the driving bands. In some cases the shaved lead remains and builds up in the die and in others is does not and being readily visible can be removed with a finger nail. In either case our bullet casting and handloading experience such did not support using a depth limiter to get the best results.

In the case of using a press you lose a large amount of “feel” because of the mechanical advantage of the press.

IOE the depth limiter was more trouble then it was worth with a potential to screw up a round that we found it more of a PIA then beneficial. Might be worth it if you are only going to mess with a single brand/configuration but IOE still not worth the effort.

If you are going to use one then you need to set it for the longest OAL and live with the slight differences in the nose shapes for shorter OAL’s.

On the PacoAcu’Rzr we did not use it after testing it out some.

Accuracy improvement relative to cast bullets primary consists of two factors. The first being the relationship between the driving bands and the throat/chamber/forcing cone for that particular weapon. Generally driving bands that are slightly larger then the throat etc. will result in maximum accuracy but there are a enough cases where that is not true….thus the word “generally”.

If you cast bullets it is common to have a variety of sizing dies for each caliber.

The second is the nose shape. The majority of lead bullet records were and still are with a flat metplat or semi-wadcutter bullet design.

Since both the Waltz and DRock sets are single dimensional resizing dies unless you happen to hit the best relationship between the throat etc. and the resized bullets there will be no discernible accuracy increase that cannot be explained by shooter performance of lack of it.

This is the Waltz die set.


This is the DRock set.

DRock sizing dies 1

The Waltz die along with the DRock die at least when we did our testing, did not tout accuracy improvement but rather making better hunting bullets and for that purpose they are excellent.


Since they are relatively simple to understand how to use I am not going into that here.

The PacoAcu’Rzr is designed not only to provide better hunting bullets but increased accuracy because it has a variety of sizing diameters which allows you to match one or even more to the throat etc. of an individual weapon.

It is the most difficult to learn how to use and the easiest to use incorrectly but offers the most versatility.

When “Paco” John says to tap the seating rods that is exactly what is needed. Any “hammering” device heavier then a light wooden meat tenderizer such as


is too heavy. You need a light weight “basher” with a fairly large contact area. You can use a wooden “sprue” handle made for knocking off the spruces on the tops of bullet molds or make your own out of a piece of wood etc. Again you don’t want anything heavier then the above.

Also whacking the snot out of the nose punch will do nothing but screw up the round.

The “myth” that you can set off a round using a “hammer” to resize it is simply that. See the testing above about that.

The largest errors in using the Acu’Rzr is to “hammer” the nose punch and/or use a too heavy “hammer”.

For the tool to work as designed you need to hold it with two fingers only and on a flat surface. Piece of hardwood works well and for those of you that still worry that you can set off a round then use that.

Flat piece of ceramic tile or aluminum etc. also works.

Personally we liked a 2”x2”x1/2” piece of hardwood or a 2”x2x1/4”” piece of aluminum as you can store those in the box the tools comes in and take the dies to the range and use them there if you want.

You then insert the desired nose punch in the desired “sizing” bored hole which looks like so.


The stamped numbers are the resizing diameters. Hard to see on the “over-sized” die on the right but one side is .226” and the other .227”


Again holding the tool loosely with two fingers TAP the nose punch until you feel it bottom out. If you drive it too deeply the tool will wobble on the “plate” and you have screwed up the round. The “wobble” is the key to using the tool correctly and also give the best results irregardless regardless of the slight original OAL variances.

Once you get into a rhythm for that session you can easily do a brick in an hour. Each person has their own rhythm. Mine is stick in the round, tap it 3 times with the above mallet and take it out ready for use.

One grandson is a “5” tapper, one is a “6” tapper and one granddaughter is a “2” tapper.

If I had to estimate, I would say that you are gonna screw up 10 rounds at the beginning of each session until you get “in the groove”. We saved those and used em for fouling shots or cold bore shots.


Over the 7 month period we fired close to 8,000 rounds for the record for the 20 weapons and about the same that were quarantined for a variety of reasons. Each shooter shot his/her weapon. Rifles were shot off a bench with sandbags for the most part and pistols were shot using the Creedmore position which many folks, me being included, consider better then a bench. Looks like so.


The weapon in the picture was not one of the test weapons.

Can also be used in hunting situations with a pistol ala.


Each set of targets were kept like in the examples above and an EXCEL® spreadsheet was made out such as.


I am not going to show each individual spreadsheet for a variety of reasons. Basically a whole pile of data, can be interpreted in different ways depending on who reads em and besides that I would have to dig em all up.

Measurable increases or decrease are +-.2” at the distances shot.


The summaries are:


15% showed measurable increases in accuracy.
70% showed no change in accuracy.
15% showed measurable decreases in accuracy.


18% showed measurable increases in accuracy.
76% showed no change in accuracy.
6% showed measurable decreases in accuracy.

Paco Acu’Rzr.

83% showed measurable increases in accuracy with many being .6” at 100 yards.
6% showed no change in accuracy.
11% showed measurable decreases in accuracy with a few being in the 1-1.5” range at 100 yards and one being almost 9” at that range. Most of the decreases in accuracy were with driving bands being smaller then the throats etc..

Here are the results and I would point out the DRock and Waltz results are buried in them.



Need to remember that those percentages are for 6 diameters, not one.
73% responded favorably by increasing the driving band diameter.
15% did not respond either way when the diameter was not resized albeit running it through the dies did make the driving bands rounder and more consistent. Debatable if that reduced fliers.
12% responded favorably by decreasing the driving band diameter. A few as low as .222”.

The most dramatic increase in accuracy was for an over-sized bore Ruger Single Six convertible. Guy that owns it really loves it and never even considered sending it back to Ruger.

Using one of the “over-sized” bore sizing diameters from the PacoAcu’Rzr it went from iffy hits on soda cans at 25 to enough hits at 50 that it was not surprising. All shooting off hand.

He stole the die and we had to take it back from him kicking and screaming for further testing.

Testing with some target grade weapons and/or target grade ammunition yielded no definitive patterns either way. IOO and IOE simply an unnecessary process.

If you think you are going to make target ammo out of bulk then you are going to be disappointed. Ain’t gonna happen!

What you can do, but not guaranteed, is make ammo accurate enough that you can use it for practice and save the expensive stuff for the matches. Even practicing bench rest. For that discipline you can practice wind deflection etc. with the inexpensive stuff and better then dry firing IOO and IOE.

Great for silhouette practice. You don’t need to be able to shoot bees off of flowers without disturbing the petals in that discipline. Can’t use in matches though.

Regardless of what type of resizer you use you must do the testing as you would for a world class match. You just cannot take 15 or 20 rounds, do them up and conclude anything.

IOO and IOE you should figure on 200-300 rounds and some really concentrated testing in a variety of conditions with a weapon that has at least 500 rounds through it.

For hunting, and a lot less testing but actual results that are still on going, all of the dies created more effective hunting rounds for small game.

If that is your purpose then chose the one that turns you on.


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