Poppers, the great Equalizer?

[Wild Gene]

*Personal note: I lost a very good friend Monday the 17th. She was a wife and mother of 3 great kids. If I seem to interject a lot, it is because it is keeping my mind off her death. The shooting community are many of the greatest people on earth.

While I tend to think calibration would be best served by a combination acheiving no more than a 105PF, I appreciate that, in general by both rule and attitude, competetors are given every chance to comply, rather than to look for a reason to exclude.

WG

[Duane Thomas]

Actually that's not just under the addendum, it's been that way for quite awhile. This was IDPA's way of not penalizing folks who choose to shoot with smaller, generally more concealment appropriate guns.

[GOF]

Duane,

It may have "been that way for quite awhile" in your perception, and maybe at the few clubs you shoot at. But, some perceptions did vary in other areas. I'm glad to see it clarified in the Rules so that a shooter in WA, ME, FL, TX or even South Africa or Italy, can now point to a firm Rule, and avoid perceptions & various interpretations of the chronograph rules.

GOF

[Gregg K]

Gregg K,

Thanks for your opinion, especially coming from a upper level revo shooter. That was also my interpretation of the new rule, I just wanted to see some conformation.

GOF

Well it's not really a new rule, it's the same as the old rule but some match directors didn't seem to read it the way it was intended. After some controversy about the way the chrono was run at times, Robert Ray from IDPA HQ issued a clarification to make sure that the procedure was run as it was originally intended. It's funny the number of different different ways a rule can be interpreted. It a real challenge for Mr. Ray to keep the rulebook small yet concise and to the point. I'm glad that I'm not in his shoes trying to keep thousands of people happy that all have different opinions about the same things. We all basically all want the same thing and that is to compete fairly and most of all have fun. I like to play several of the different gun games and have fun at all of them.

[Duane Thomas]

I'm just saying this rule has been in the Rule Book prior to the previous clarification, it's not like this is a new thing. "Some people weren't aware of it" and "It didn't exist" are not the same thing.

[Sam]

Load to well above minor. People load minor because they think it gives better recovery. Good form is what gives better recovery.

If you learn to shoot 145-150 pf loads, the recoil impulse is still pretty wimpy. In fact, minor loads (125 pf) are harder to shoot if you practice with hotter loads. Try loading to get the advantage of a knock-down with a less than perfect hit. Higher PF is more forgiving. And the gun is often more reliable with hotter loads. Think of riding a 125cc dirt bike vs a 400cc scooter. Learn to use the powah!. The recovery time of the warmer load is negligable if you get used to a snappy load.

just my 2 cents and and extra 250cc's

[Wild Gene]

Load to well above minor. People load minor because they think it gives better recovery. Good form is what gives better recovery.

If you learn to shoot 145-150 pf loads, the recoil impulse is still pretty wimpy. In fact, minor loads (125 pf) are harder to shoot if you practice with hotter loads. Try loading to get the advantage of a knock-down with a less than perfect hit. Higher PF is more forgiving. And the gun is often more reliable with hotter loads. Think of riding a 125cc dirt bike vs a 400cc scooter. Learn to use the powah!. The recovery time of the warmer load is negligable if you get used to a snappy load.

just my 2 cents and and extra 250cc's

I used to shoot Cowboy with a guy that shot Duelist, one handed, that shot .45's for that very same reason. He needed the rock to get a rythm. He would always end up at the top of the pack and any match he went to, to the highest level.

WG

[T Bacus]

I haven't run matches in quite a long time but when I did I did it a lot, and my first rule of thumb was don't do anything to make problems for myself. Trying to police power factor with reactive targets is only going to cause you as the match director headaches. If you have a need to ensure that competitors are using pf legal ammo then set up the chrono. I ALWAYS set steel so that it would fall if you looked at it hard.

If you believe that some competitors are using sub pf ammo in an attempt to cheat then pull their ammo when they aren't expecting it and chrono it. As for competitors loading to 105 in a 4" barrel and then shooting a 2" for less recoil, why in the world would someone do that. Any advantage gained in lower recoil is lost by virtue of the shorter gun being harder to shoot accurately. People weren't doing this at 125pf and they won't be doing it at 105.

[Forrest Halley]

You forgot that a model 10 snubbie with JM grips is a 0 seeking wonder drug and with the new 105 PF it will be all the rage. Load up nice light 9mm bullets and send them screaming downrange with 3.5 to 4.0gr of clays behind them and master classification is just 90 trigger pulls away.

Does anybody really believe recoil gets lighter as the gun gets lighter? If so I've got a glorious .357 load for you to test your theory out with...

[RePete]

So basically the competitor's load/gun doesn't have to make PF. The option exists to chrono out of a full length gun under the new addendum. What Bones says about compliant competitors all recieving the same chance to succeed is spot on. I ask how can a competitor be considered totally compliant if their gun/load combo does not make PF? The point of the load making PF in a gun not being used for the competition is moot. There should be no reshoot awarded for a competitor that takes this route. The steel must fall to score and since the presence of steel makes for unlimited shots setting it to fall with a center hit from a 105PF combination seems an honest and fair method.

The load will have to make PF from a barrel length that is maximum to the division.

Revolver is 4".

If you are using a 2 or 2 1/2" barreled revolver, your ammo may not make PF from your gun - that's OK - it will have to make PF from a 4" revolver. If no 4" isn't available at the chrono then your ammo is deemed to meet the required PF.

FWIW I'm running the chrono at this years NY State IDPA Championships. I have a 4" that will be used.

Edited February 10, 2011 by RePete

[rvb]

If you are using a 2 or 2 1/2" barreled revolver, your ammo may not make PF from your gun - that's OK - it will have to make PF from a 4" revolver. If no 4" isn't available at the chrono then your ammo is deemed to meet the required PF.

Maybe I missed it, but this is the key point that I hadn't seen and was about to make myself. People aren't shooting snubbies to try to reduce pf and therefore recoil, they are shooting them because that's what they carry. And this is where honest shooters get bit by the rules if we don't give the benefit of the doubt to the shooter. If you have to give a "pass" to a shooter, that's a problem with the rules, not the shooter.

[edit: ok, I now realize the addendum says you have to make it in your gun if no max-length gun is available... that's slightly better, but not consistant across all shooters. And a real penalty to those who want to shoot what they carry]

btw, what is the max barrel length for the auto divisions?

-rvb

Edited February 10, 2011 by rvb

[Forrest Halley]

btw, what is the max barrel length for the auto divisions?

-rvb

It's a "fits in the box"...I wonder why somebody hasn't taken their gun apart and put it in the box. There is nothing that says it must be assembled....or ready to shoot...or functional. Any idea if a six inch STI will fit in piece into a box? Why don't we have "compliance" mode and then "defensive" ooops wait I meant "Competitive" mode. I want the lunchbox glock that the goes from suitcase to shoulder fireable I bet it'll fit....

I have to say there is some definite equipment racing going on in side the IDPA box. There's always gonna be a better way to build a mousetrap...XD 3.8? Built for bug gun matches? How about they just come to some sense and say look folks your concealment garment can only extend five inches below the bottom of your belt. Nothing can stick out from underneath and nothing can print below the bottom edge of the concealment garment. All the long barrels can all go IWB and everybody has a great time. Besides I'd like to put my cigars back in their box.

[rvb]

btw, what is the max barrel length for the auto divisions?

-rvb

It's a "fits in the box"...I wonder why somebody hasn't taken their gun apart and put it in the box. There is nothing that says it must be assembled....or ready to shoot...or functional. Any idea if a six inch STI will fit

Exactly my point and the reason I asked the question. (Usually when I ask this I get, "well, 5", of course!") The bones are broken, and when the first band-aid doesn't solve the problem, more and more bandaids get added. No max bbl length is defined like the esr/ssr/bug divisions. The box is 8.75" so is that the max bbl length? or is it the diagonal measurement of 10.6"? Does the size of the box even matter? There is no rule that the gun used for chrono purpose has to fit in the box. The bbl of my ssp gun is ~4.2", can I bring a 16" 9mm AR for chrono?

Not trying to be a "DRL," but I'm an engineer. my first question when I see something like this is "what is the max?" And I can't find an answer.

Meanwhile... an impact of the issue is "how do I set up poppers." Can I get Snoopy on my bandaid, please?

How does this affect me? Well, I never shoot revo and my auto loads are at least 8pf over w/ MY gun, so I really don't care. But the popper better fall when I hit it in the circle or higher or I expect a reshoot.

-rvb

Edited February 10, 2011 by rvb

[RePete]

The maximum barrel lengths are given forr revolvers only. All others have to fit the box.

SSR = 4"

ESR = 4"

[GSWEAR]

The maximum barrel lengths are given forr revolvers only. All others have to fit the box.

SSR = 4"

ESR = 4"

I may be mistaken but I think it is 4.2" for the revo's.

I think there is a GP100 that's about 4.2 and I think S&W is coming out with one but as usual I may be wrong.

Greg

[RePete]

The maximum barrel lengths are given forr revolvers only. All others have to fit the box.

SSR = 4"

ESR = 4"

I may be mistaken but I think it is 4.2" for the revo's.

I think there is a GP100 that's about 4.2 and I think S&W is coming out with one but as usual I may be wrong.

Greg

Correct.

I was thinking of my 4" Smith at the time.

[gr7070]

...I think S&W is coming out with one but as usual I may be wrong.

Greg

The below link was posted on the S&W forum. It's from a Canadian dealer - Canada has laws restricting < 4.2" bbls.

http://www.badgerarmssupply.com/index.php?page=smithwesson

Scroll down.

Edited February 11, 2011 by gr7070

[John Z Sr]

You guys keep argueing all the rules, I'm going to the loading bench, 3 IDPA matches to shoot this weekend, for me, triggers are more fun than keyboards

[Forrest Halley]

You guys keep argueing all the rules, I'm going to the loading bench, 3 IDPA matches to shoot this weekend, for me, triggers are more fun than keyboards

Oh yeah? In my quest to be better than matchmaster....I'm shooting steel this weekend...poppers galore! IDPA next weekend.

[atbarr]

Oh yeah? In my quest to be better than matchmaster....I'm shooting steel this weekend...poppers galore! IDPA next weekend.

Yep, Steel tomorrow, IDPA next Saturday.

A.T.

[T Bacus]

Loading power factor for a 4" barrel and then shooting that same load out of a shorter barrel does NOT reduce felt recoil.

A load that makes a 105pf out of a 4" barrel 686 will have less felt recoil than the same load shot when from a 2.5" 686. Fire it from a 2" Model 10 and it will have even more felt recoil. Each gun may develop a different velocity but the pressure of the load is the same regaurdless of the gun it's fired from. When using the same ammo gun weight determins felt recoil, not velocity. Anyone here want to argue that a 38 Special 125gr+P load kicks less when fired from a 2" snubby than when fred from a 4" heavy barrel Model 10?

Another way of looking at it. Develop the perfect 105pf load for your 4" model 10. Then take a Hacksaw and cut two inches off of the barrel. Do you now think the gun will kick less?

Edited February 17, 2011 by T Bacus

[Steve Koski]

I'm not so sure. My 4" 500 S&W Magnum had less felt recoil than my 8" gun with the same loads. The smaller gun was a lot louder, and a bit lighter, but it also dropped ~250 fps of velocity.

[Gregg K]

I'm not so sure. My 4" 500 S&W Magnum had less felt recoil than my 8" gun with the same loads. The smaller gun was a lot louder, and a bit lighter, but it also dropped ~250 fps of velocity.

It depends on the load and how much powder you are burning. I'll give an extreme example..

In the case of a .50 BMG rifle, a gun with a 16" barrel will have much less recoil than one with a 32" barrel when they both have the same muzzle brake even though the 32" gun weighs more. The 16" barrel blows half of the burning powder out the muzzle before it can continue to build pressure. It takes about a 32 to 36" barrel to burn 220 grains of powder. Recoil has many variables besides gun weight.

Like your 4" 500, a 16" 50 BMG with a 16" barrel and a muzzle brake is just nasty loud.

[Forrest Halley]

I'm not so sure. My 4" 500 S&W Magnum had less felt recoil than my 8" gun with the same loads. The smaller gun was a lot louder, and a bit lighter, but it also dropped ~250 fps of velocity.

I never knew 500's to have any percieved recoil...Probably because I was so awe struck by the 3' diameter beachball of flame coming out the other end and the possibility of the gun going into high earth orbit. I believe percieved recoil to be something to do with the weight of the gun and the muzzle energy. Barrel length having anything to do with it is snake oil.

Retest your theory with 440gr hardcasts. That was mostly what I shot. I think what hurt most was the elbows from the heavy gun coming back down from the muzzle flip and perhaps your 8.375 doesn't flip as badly. The comp are most likely different also. I only used the Jacketed comp because it worked better.

[Bones]

Loading power factor for a 4" barrel and then shooting that same load out of a shorter barrel does NOT reduce felt recoil.

A load that makes a 105pf out of a 4" barrel 686 will have less felt recoil than the same load shot when from a 2.5" 686. Fire it from a 2" Model 10 and it will have even more felt recoil. Each gun may develop a different velocity but the pressure of the load is the same regardless of the gun it's fired from. When using the same ammo gun weight determines felt recoil, not velocity. Anyone here want to argue that a 38 Special 125gr+P load kicks less when fired from a 2" snubby than when fred from a 4" heavy barrel Model 10?

Another way of looking at it. Develop the perfect 105pf load for your 4" model 10. Then take a Hacksaw and cut two inches off of the barrel. Do you now think the gun will kick less?

I do not wish to argue, but if a competitor selects a shorter barreled gun with the same weight, the laws of physics tell us the felt recoil will indeed be reduced. No matter what attribute of recoil you select - momentum, impulse or energy - the shorter barrel wins every time. This is especially true in non-reciprocating firearms such as revolvers where the slide lock time and return velocity complicate things.

If the gun mass stays the same (i.e. a 2" 686 vs a 4" model 19, both weighting about 39 oz with Pachmayr grips) a load that develops less velocity with a given projectile produces less felt recoil. Both muzzle velocity and felt recoil are based of the same projectile weight and pressure curve. The short barrel burns less powder, which is why it produces less pressure, and hence, velocity. Also remember the the lever arm (the highest point of the muzzle as the bullet exits and the highest point on the dominant hand) is also reduced, thereby reducing muzzle lift.

What formula are you using for felt recoil?

For instance, this is what I am referencing relative to momentum:

p_f + p_p = 0\,

where p_f\, is the momentum of the firearm and p_p\, is the momentum of the projectile. In other words, immediately after firing, the momentum of the firearm is equal and opposite to the momentum of the projectile.

Since momentum of a body is defined as its mass multiplied by its velocity, we can rewrite the above equation as:

m_f \times v_f = m_p \times v_p

where:

m_f\, is the mass of the firearm

v_f\, is the velocity of the firearm immediately after firing

m_p\, is the mass of the projectile

v_p\, is the velocity of the projectile immediately after firing

You can see that the mass and velocity of the projectile are both directly proportional with felt recoil. There fore a lower velocity with the same projectile will produce a proportional reduction in felt recoil in a gun of the same mass. Velocity is even more important when considering the energy or impulse equations.

I agree with you that if you lighten the same gun the physics get more complicated (i.e. cutting 2" of barrel off a 4" Model 10). Even then the physics will favor a 50 fps loss in velocity (off a 665 fps/158 gr - 105000 PF - starting point) over the 1.5-2.0 oz reduction in weight. Run the numbers yourself. The physics "gets worse" on shrouded ejector rod models such as the 19 or 66 where the reduction in mass from shorting the thin part of the barrel assembly proportionally reduces the weight even less.

I also agree that perceived recoil is arbitrary and somewhat subjective - muzzle blast and sound affect some people more than others - but I do not understand the physics supporting your statement about felt recoil.

All else equal, I would rather shoot a Model 10 that produced 600 fps than one that produced 700 fps regardless of barrel length if both produced equal sized groups with any given load at IDPA distances.

This is why I continue to believe the only fair way to assess competitors is to require them to show compliance with power floor settings from the same gun used in competition regardless of barrel length. It is more straightforward, fair and easier to officiate. IPSC, USPSA, ICORE and NRA Action Pistol all agree.

We now return you to your regularly scheduled program.

Craig