Dan Theodore - Clean Rifle and 6th Shot Effects For Blow Tubing and Wiping Between Shots


This past weekend testing with three different lubes was undertaken.  The experiment focused on several effects that match shooters are confronted with during matches that can reduce their scores.  Each of these effects was tested for by using a blow tube for the first 10-shot string and then a wiping technique for the next 10-shot string for each of the three lubes tested.

 

The first effect tested for was the velocity variation caused by a clean barrel and how quickly the velocity settled down and the core group formed.  The next was the so called “6th Shot Effect”.  For those that shoot BPCR Silhouette, you know what is meant by the most unfortunate “6th Shot Effect” and have suffered the mind bending consequence.  It is the accuracy or lack thereof of the first shot at the second bank of animals after the break period.  Many of us have seen the result, a missed 6th target.  We are often at pains concerning whether to correct the rear sight after the 6th shot or leave it as is.  That decision can cause the next shot to hit dirt instead of steel, two misses in-a-row.  Finally, a new lube component was tested to see if any benefits could be had from adding it to White Lightning BPCR Lube.  Results look mighty promising so read on.

 

The weather conditions were nice for this time of year.  Testing for this series of experiments started at about 11:30 AM up at the Los Altos Gun Club in the beautiful Santa Cruz Mountains above San Jose, CA.  The sun was shinning with temperatures that stayed in the low to mid 40’s during the testing with humidity fairly constant at about 61 %.  The wind was light and variable.  All testing was done at 100 yards, off-the-bench with iron sights.  An Oehler P35 chronograph was used.  It was placed about 15 feet from the muzzle.

 

Three lubes were tested to investigate the effects discussed in the first paragraph: White Lightening BPCR Lube (WL) for grooved bullets, WL with a special additive and a popular commercial lube (not SPG).

 

The rifle used for the testing was a Pedersoli John Bodine 45-90 with Baldwin front and rear sights.  A Lyman Postell bullet weighing in at 530 grains, when cast in 20-1, served as the lube carrying vehicle.  The load was 80.0 grains of Swiss 1.5 with about 40/1000” compression, F150M primer, 60/1000 LPDE wad over the powder, slip-fit bullets hard into the lands and Buffalo Arms stretched brass.  No over-primer-wad was used.  The rounds went into the chamber with just a bit of a push on the rolling block breech lever.  The bullet’s first driving band was completely engraved by the freebore.

 

The testing protocol was as follows.  Each string of 20 rounds (2 x 10) with a particular lube (60 rounds total for all three lubes tested) started with a clean barrel and the rifle sitting for about 10 minutes (target checking and changing period between 15 minute firing periods) so the barrel was about ambient temperature at the start of each 10-shot string-of-fire.  There was also a 10 minute break between shots 10 and 11 within a particular lube test.  The first 10 rounds were shot using a blow tube, the 10 minute break period preceded shots 11 though 20, but this time the barrel was wiped between shots.  The wiping process used required a patch dampened with distilled water to be pushed  slowly through the barrel with a nylon brush (caliber size) attached to a flexible rod.  When the patch dropped from the barrel the brush was drawn back to the chamber and then pushed to the muzzle and back again before inserting the next round.  The cleaning process between lubes tested was to wet patch and brush to remove fouling, dry patch, oil patch with Kroil and dry patch again.  Three exhales of about 3 seconds each were used for the blow-tubing part of the testing for each of the three lubes.  During the string-of-fire MV’s were recoded on the chronograph printer.

 

A sample string-of-fire was as follows.  First shot for the 20-shot string of a lube type was from a clean, cold barrel.  The first 5 shots using the blow tube were shot with a typical BPCR Silhouette match cadence.  After the 5th shot a 2-minute break was taken to simulate the break in a silhouette match.  Next the 6th though 10th rounds were fired using the blow tube.  By then, it was time for a cease-fire.  Upon commencing fire after the break the barrel was wiped using the damp patch process and the next 5 rounds were fired wiping between shots.  A 2 minute break was taken, the barrel patched and then the remaining rounds, 16 through 20, were shot using the wiping process.  After 20 rounds were fired with a particular lube the barrel was cleaned using the above cleaning process.  This sequence was repeated for all three lubes tested.

 

The results of the testing were insightful.  For each of the 3 lubes tested the groups are shown below the chronograph data for each 10-shot string.  Both 10-shot groups were shot on the same target for each lube tested.  Also, before the first test-string was fired 10 rounds were fired and then the barrel cleaned so there was no bias in the first group tested with the rifle.  The rifle then sat for about 10 minutes before initial testing commenced.  This series of lube tests was the third in a series that day, the first being load testing with a 7mm PPC Improved Wichita pistol followed by a 38-70 for 30 rounds.

 

 

Popular Commercial Lube - Blow Tubing Between Shots:  As you can see from the velocity progression below it took 2 rounds for the velocity to settle down.  From the target below the velocity statistics the high shot was shot 6, but the velocity was still in the settled-down range.  Why that happened I don’t know yet, but we have all seen that at times with our 6th shot for record in BPCR Silhouette.  This is also a problem in Target Rifle matches after waiting for a condition.  The dilemma when that happens is do we correct or stay the course with the rear sight.  Once the velocity settled down after two shots the high was 1,255 fps and the low was 1,246 fps for an extreme spread of 9 fps.

 

Shot # - Velocity (fps)

1                    - 1,278 – First Shot excluded

2                    - 1,265 – Second Shot excluded

3                    - 1,249

4                    - 1,252

5                    - 1,254

6                    - 1,246 – Low Velocity – 6th Shot

7                    – 1,247

8                    – 1,248

9                    – 1,247

10                – 1,255 – High Velocity

 

Below is the properly scaled target for the above velocity string.

 

 

Popular Commercial Lube - Wiping Between Shots:  As you can see from the velocity progression below the first shot had a “standard” velocity.  There was no “6th shot” effect as that bullet went into the group.  The high velocity was 1,274 fps and the low velocity was 1,255 fps for an extreme spread of 19 fps.

 

Shot # - Velocity (fps)

11                - 1,265

12                - 1,266

13                - 1,255 - Low Velocity

14                - 1,260

15                - 1,257

16                - 1,265 – 6th Shot

17                – 1,274 - High Velocity

18                – 1,260

19                – 1,271

20                – 1,263

 

Below is the properly scaled target for the above velocity string.

 

 

It seems that wiping, if using a commercial lube, is better than blow tubing, the vertical dispersion says it all.  And, my bet is the problem will become more exaggerated as the temperature climbs and humidity drops.

 

 

White Lightning BPCR Lube - Blow Tubing Between Shots:  As you can see from the velocity progression below it took 1 round for the velocity to settle down after the barrel was completely cleaned.  From the target below the velocity statistics one can see the first shot at the top of the target.  The next 4 shots are just below it in a single hole.  The 6th through 10ths shots are in the group to the left.  The group shifted about 1” to the left probably as a result of changing how the rifle was gripped between the first and second string of 5 shots.  When my trigger-hand thumb is wrapped over the tang, shots tend to go right.  I typically place my thumb, in a relaxed manner, on the right side of the action when shooting, but I must have spaced-out and wrapped my thumb over the tang for the first string-of-fire as that nasty habit was ingrained a long time ago and rears its ugly head now and then when I space-out.  As you can see from the group there was no “6th Shot Effect”.  Once the velocity settled down after the first shot the high was 1,252 fps and the low was 1,247 fps for an extreme spread of 5 fps.  When using this lube during matches and GG bullets are used I’ve found, as well as others using this lube, that the first sighter shot is in the group as long as the barrel is not cleaned.  In my opinion that is a substantial benefit to match shooters.  The technique used between relays is to not blow tube after the 10th shot for record and only blow tube when going for the next sighter shot on the next animal or next target in Target Rifle competition.  It is my opinion that more barrels are ruined by “cleaning” than shooting, so think about why you are cleaning your barrel between relays.

 

Shot # - Velocity (fps)

21                - 1,286 – First Shot excluded

22                - 1,250

23                - 1,248

24                - 1,249

25                - 1,248

26                - 1,250 – 6th Shot

27                – 1,250

28                – 1,251

29                – 1,247 - Low Velocity

30                – 1,252 - High Velocity

 

Below is the properly scaled target for the above velocity string.

 

 

White Lightning BPCR Lube - Wiping Between Shots: As you can see from the velocity progression below, the first shot had a “standard” velocity.  There was also no “6th Shot Effect” as that bullet went into the group.  The high velocity was 1,266 fps and the low velocity was 1,255 fps for an extreme spread of 11 fps.  Maybe some work needs to be done to develop an improved wiping technique as blow-tubing had ½ the MV extreme spread, not that the wiping ES is unacceptable, but this is an interesting proposition that lights the fire of curiosity.  I just might have to work harder on developing grease groove bullets that have higher BC’s than grooveless bullets because at Creedmoor distances I’d love to have an ES for a string of fire of 5 verses 11 fps, not that 11 fps is unacceptable, but 5 fps would be more sweet to be sure.  The grooveless bullets have not performed as well with blow-tubing as per my testing.  Some of the guys using WL Dipping Lube have shown superior match results using a blow tube with grooveless bullets.  Stu Harvey comes to mind.  At our last Creedmoor match he was able to shoot his 12-twist, 38-55 original length chambered rifle quite well with a duplex load of 4.5 grains of RL7 under 45.0 grains of Swiss 1.5 that launched a 1.40” long PJ 5G grooveless bullet.

 

Shot # - Velocity (fps)

31                - 1,265

32                - 1,263

33                - 1,265

34                - 1,255 - Low Velocity

35                - 1,257

36                - 1,259 - 6th Shot

37                – 1,266 - High Velocity

38                – 1,256

39                – 1,259

40                – 1,259

 

Below is the properly scaled target for the above velocity string.

 

 

 

 

White Lightning Extreme  BPCR Lube With Special Additive -  Blow Tubing Between Shots:

As you can see from the velocity progression below there were no settling-down shots for the velocity even from a clean barrel while using a blow tube.  This research and development effort has been ongoing for the past 3 months.  It finally looks like progress is being made after a lot of burned powder and lead down range.  Certainly more testing is required, but so far, so good.  From the target below the velocity statistics one can see the first shot from the clean barrel was in the group.  I believe this is an advantage when one is match shooting as time and ammo are saved as well as barrel heating reduced in hot conditions.  A first shot, with this lube formulation, can count for rear sight adjustments instead of cooking off a few rounds and then getting serious about sight adjustments.  This is especially helpful when shooting as fast as possible to keep in a wind condition, my main motivation as I like to shoot like a single-shot BPCR machinegun if the condition holds.  I’ve gotten off the line in not much more than 6 minuets in a Creedmoor match when the wind is favorable (and pit crew are cooking) at the beginning of the string of fire.  A lube that will allow me to bang-off 10-shots for record in minimum time is a substantial advantage, no if’s ands or butts.   Sorry about the pun, I just couldn’t help it.  Also, the lack of the “6th Shot Effect” when one is using a blow tube, IMHO, is a very neat thing when shooting a BPCR silhouette match.  This will also be most helpful when shooting Target Rifle Matches due to the fact that waiting on a wind condition can produce that “6th shot effect.”  Some guys continually huff on their blow tube waiting for the condition to come back, but my testing has shown that this will also produce the undesired effect, lack of that next bullet going into the group.  The below first shot velocity was a “standard” velocity.  The high was 1,253 fps and the low was 1,246 fps for an extreme spread of 7 fps.

 

Shot # - Velocity (fps)

41                - 1,252

42                - 1,247

43                - 1,246 - Low Velocity

44                - 1,253 - High Velocity

45                - 1,247

46                - 1,246 – 6th Shot

47                – 1,248

48                – 1,247

49                – 1,247

50                – 1,250

 

Below is the properly scaled target for the above velocity string.

 

 

White Lightning Extreme  BPCR Lube With Special Additive - Wiping Between Shots:

As you can see from the velocity progression below the first shot had a “standard” velocity.  There was no “6th shot” effect as that bullet went into the group.  The high velocity was 1,256 fps and the low velocity was 1,247 fps for an extreme spread of 9 fps.

 

Shot # - Velocity (fps)

51                - 1,255

52                - 1,249

53                - 1,254

54                - 1,247 - Low Velocity

55                - 1,255

56                - 1,254 – 6th Shot

57                - 1,254

58                - 1,255

59                - 1,256 - High Velocity

60                - 1,254

 

Below is the properly scaled target for the above velocity string.

 

 

 

So, what do I think I learned?  First of all it was obvious that a typical commercial lube composed of large amounts of beeswax required two rounds through the clean barrel when a blow tube was used before one could have confidence with sight corrections.  It remains to be seen how many rounds would be required if one wipes between shots and starts with a clean barrel as the testing for the 10-shot wiping test started with a well fouled barrel.  Next, the commercial lube produced a nasty “6th Shot Effect” flyer that would have gone over the back of any of the animals or into the “white” for Target Rifle shooting.  Certainly this is a limited test, but that effect has been seen by many during matches.  There was also more vertical stringing for the beeswax-based commercial lube whether a blow tube or wiping was used.

 

WL, using a blow tube, required only one shot before the velocity settled-down when starting with a clean barrel and there was no 6th shot effect.  Wiping with WL also produced fine accuracy and velocity variation.

 

The latest version of development lube, WL Extreme, is showing promise, especially when a blow tube is used.  This result, though limited in scope, is motivation enough to continue testing this particular formulation with a series of “tweaks” to the special additive.  This special formulation also produced fine accuracy and velocity variation when wiping between shots.

 

In conclusion this new additive shows exciting potential for shooting grooved bullets.  Much more testing is required as the above 3-lube test will be repeated in 80 F and 100 F temperatures.  This test showed the results of cool weather.  The results could be quite different in hot, dry conditions.  But, after thousands of rounds testing lubes and applying what I think I know, the results in harsher conditions will only accentuate the results gathered in cool, humid conditions.  Much more later as the 2005 season heats up.

 

One final comment, one of the design parameters that drove lube development was to reduce lube hardening variation as a function of air, barrel and cartridge temperature.  I believe that is why WL has been shown to be more temperature insensitive when it comes to accuracy and velocity variation than most lubes.

 

For those of you that like to look at experimental data and chew on it, below is a table compellation of the test data.


This table contains the test data in the order of execution.

 

Shot #

Commercial Blow Tube Clean Barrel

Commercial Wipe Fouled Barrel

WL Blow Tube Clean Barrel

WL Wipe Fouled Barrel

WL Extreme Blow Tube Clean Barrel

WL Extreme Wipe Fouled Barrel

1

1,278       Shot Excluded

1,265

1,286 Shot Excluded

1,265

1,252

1,255

2

1,265       Shot Excluded

1,266

1,250

1,263

1,247

1,249

3

1,249

1,255

1,248

1,265

1,246

1,254

4

1,252

1,260

1,249

1,255

1,253

1,247

5

1,254

1,257

1,248

1,257

1,247

1,255

6

1,246

1,265

1,250

1,259

1,246

1,254

7

1,247

1,274

1,250

1,266

1,248

1,254

8

1,248

1,260

1,251

1,256

1,247

1,255

9

1,247

1,271

1,247

1,259

1,247

1,256

10

1,255

1,263

1,252

1,259

1,250

1,254

MV Avg

1,250

1,264

1,251

1,262

1,251

1,255

MV High

1,255

1,274

1,252

1,266

1,253

1,256

MV Low

1,246

1,255

1,247

1,255

1,246

1,247

Velocity ES

9

19

5

11

7

9

SD

3.5

5.9

1.6

4.0

2.5

2.9

 

 

Postscript: Clean Rifle and 6th Shot Effects

 

Guys, after chewing on the test data and preliminary conclusions for a while, more issues and thoughts that should have been included in the above report are discussed below.  I think some of you might find the ideas interesting.  They have been spinning about the brain for quite some time.  Of late I’ve gotten back into trying to work out the solutions or at least a better understanding of the cause and effects.  It seems the more I learn the more I know I don’t know very much.

 

At this point in the efforts to better understand how to make all the BPCR bullets, for a string of fire, go into the same hole, knock all the belly animals over and keep all the shots in the X-ring a nagging concern keeps creeping back into my brain.  That nagging concern is coefficient of friction between bullet and barrel.  It seems that at the level most of us are at with regard to competent casting, reloading and trigger pulling something out there is keeping us from higher levels of accuracy and match performance from a BPCR equipment (rifle and load) standpoint.  The odd, unexplainable flyers that kill our match performance or ruin a group during testing are not, in my mind a function of our skill, load or rifle.  No, I believe we are often tripped up by inconsistent coefficient of friction between bullet and barrel and there are often compounding consequences that precipitate from that stumble under the stress of match shooting, that is we miss another animal or “X”.

 

We know how to cast excellent bullets; how to make sure every bullet seated has a perfect base; weigh our powder charges to 1/10 grain; use excellent primers; control neck tension or don’t use any; our rifles are top notch; we know how to hold the rifle consistently, align the sights, break a clean shot, follow through and call the shot.  But yet we all have those nasty unexplained flyers that can destroy match performance or test group.  And, that “flyer” eats at our brain; “Was it a flyer or do I need to adjust the rear sight because of something in the wind condition we can’t see moved the bullet?”

 

For those of us striving to improve match performance, that can be, and often is, a serious quandary.  We have all had it happen to us and we’ve heard shooters and coaches discuss the “flyer” issue while agonizing over what to do; take the next shot without a sight correction or crank on the rear sight.  It is far too easy to go down the proverbial rat hole chasing a flyer with a sight correction.  And, not correcting for the condition can put us in the same place if we don’t trust our rifle and load.  Confidence that our combination of rifle and load DO NOT produce flyers is key to making the correct decision with regard to making sure the next shot is in the X-ring or next animal is in the dirt.  There is noting like cleaning the first bank of rams, missing the 6th and then cranking or not cranking on the rear sight only to miss the 7th ram.  That can really put you into the proverbial grand funk.  Remember those guys?  I think they had a railroad:-)

 

With that in mind, and the testing conducted over the past few years, it seems that controlling the friction between bullet and barrel is the proverbial “last mile” once all of our other ducks are in-a-row.  Even if the fouling is soft while using a blow tube the friction can be quite different.  Over a chronograph it is possible to prove that sufficient blow tubing will produce a given MV profile while excess blow tubing will also keep the fouling soft and produce a different MV profile, generally with more MV variation.  The same is true with much more dire consequences if insufficient moisture is transmitted to the barrel.  There is a narrow range of moisture content in the fouling that will produce a narrow range of MV and top accuracy.

 

From my current perspective, there are two areas of optimization that address this “last mile” issue of consistent friction between bullet and barrel.  One area I believe most of us work on is to exhale the same quantity of moisture into the barrel (also contact time is important, length of time moist breath is in contact with the fouling) and shoot with a consistent shot-cadence to reduce moisture content variation shot-to-shot from evaporation (barrel heat increase through the string-of-fire and ambient temperature & humidity).  Whether we can achieve consistent moisture content is another question that still goes unanswered.  The hotter and drier the condition, the more difficult the maintenance of consistent moisture content in the fouling becomes.  And, testing has shown that moisture content affects the coefficient of friction between bullet and barrel with the lubes most of us use.  

 

It has been my experience, after many thousands of rounds of accuracy testing with BPCR’s, that they shoot best in cool, damp conditions.  The barrel does not heat up much (low barrel temperature variation shot-to-shot); the moisture content in the barrel stays relatively consistent with regard to shot cadence; life is good.  However, we rarely have such luxury out west.  I believe the east coast shooters have an easier time of this as they are rarely confronted with what we call dry conditions.  But, they also need to work on friction consistency for optimum accuracy.

 

The second area of optimization is to develop a BP lube that is relatively insensitive to moisture content with respect to coefficient of friction between bullet and barrel.  One thing learned from research and testing to date, in that domain, is that waxes are sensitive to temperature so far as their hardness and therefore to their contribution to friction in the fouled barrel.  Therefore, as the barrel heats-up during the string-of-fire the coefficient of friction is changing shot-to-shot.  This effect is minimized in cool conditions, but in hot  conditions this becomes a substantial issue when striving to maintain top accuracy.  Removing wax from BPCR bullet lube is, in general, a step in the right direction when we are interested in controlling friction variation.  How to do that and still have a lube that can be applied with the typical lubing techniques is an interesting proposition.  Pan-lubing is the most difficult.  Lubesizing is not too difficult and dip-lubing is a slam-dunk.

 

Even if we can’t maintain a high degree of friction consistency between bullet and barrel in harsh conditions as long as we are doing better than our competition we have an advantage.   Those that are doing worse for a variety of reasons are at a disadvantage.  To be able to maintain this friction consistency over a wide range of conditions is a seriously difficult objective, but as long as we are doing better than the rest of our competition we have the competitive edge.

 

There are a number of design parameters for optimizing lube, but friction consistency between bullet and barrel is, I believe, the one that will help push us past the “flyer” problem and the compounding ramifications of poor decision outcome for the next shot under match stress.  We still need a lube that will withstand harsh conditions; cold and dry, as well as hot and dry.  But this issue of friction being a function of moisture content while the barrel is increasing in temperature during the string of match fire presents a sticky wicket as our British brothers would say.  If we blow tube consistently during the record string of fire the barrel fouling is not absorbing and retaining the same amount of moisture as the barrel is heating up and our rate of fire depends on a number of things; waiting for a condition, need to discuss the last shot more, etc.  So this issue of having consistent moisture content in the fouling at the moment the round goes off, shot-to-shot, is indeed a very sticky wicket that gets stickier as the weather conditions become harsher.

 

It seems to me that we need to address the issue of developing moisture insensitive lubes with regard to coefficient of friction between bullet and barrel.  How that can be done is the focus of ongoing research and testing as you’ve seen.

 

For those of us that are Target Rifle shooters, the mid-summer sun will heat up a barrel very quickly in conjunction with the heat of powder combustion and bullet friction.  This issue makes it even more difficult to maintain a consistent friction coefficient within the necessary range, whatever that is, to maintain MOA accuracy.  Two years ago when my shoot’en pard, Rick Eskite won the Prone Target Rifle Nationals at Raton, he was doing great at 600 yards with maybe 1 or 2 dropped points going into shot 8.  His accuracy took a nosedive into the outer black and white.  His barrel had fouled out in 94 F and 24% humidity conditions.  We had shot in that kind of condition and much worse with no fouling problems, but in the shade during BPCR silhouette matches.  It seems that the Target Rifle shooters have an even greater opportunity for improvement in working to maintain the friction coefficient within some range due to increase barrel heating.  If Rick’s barrel had not fouled out he would have added between 6 and 9 more points to his score.  I went up and down the line after that relay.  Each shooter I talked to had fouled out.  If one of the other contenders had not fouled out they could have taken the National Championships.

 

A lube that can help address these challenges must be temperature insensitive to variation in friction coefficient, as well as insensitive to moisture content, as a function of the coefficient of friction between bullet and barrel as well as be aggressively hydroscopic after combining with BP combustion residue to function properly in harsh conditions.  A tall order for sure, but that is, of course, the interesting part.