Need .45acp Load For Idpa/cdp

[Nick Weidhaas]

I just started shooting IDPA. Shot my 1st classifier (CDP) and made Expert, just short (4.49) of Master. I shot 230gr. ball (S&B factory). In addition to some specific practice, it was suggested that I handload a 200gr. bullet at the 170pf as it would be softer and have less muzzle flit than what I'm shooting now. I last loaded 45ACP about 6 years ago so I am a little out of the loop here. I'm also not sure what the velocity of the S&B is out of my gun so I don't have a pf.

For those CDP shooters out there, would you recommend I go with a handload or stay with the facory S&B 230gr. ball. If handload, what load would you recommend. I have a Dillon 550, Winchester cases, Winchester and Federal Primers and Clays powder available. I have no bullets and don't know what to go with. I'm shooting a Vic Tibbets built Colt 1911 with a 14lb recoil spring. (I tried a 13lb spring buy my shock buff was cut ot ribbons).

Any advice would be appreciated.

Thanks,

Nick-

[Rufus The Bum]

Man, if you dang near made Master in your first go around, why change loads? If you want to reload, I use about 4.3 of Titegroup in my 230's and it comes up to right around 165pf. Congrats on your accomplishment

[Gun Geek]

Nick:

Here's what I shoot for IDPA - a 255gn SWC over 3.1gn of Clays. The reason I do this is to keep the recoil down! I've seen a couple of threads about this on this forum, as well as explored it a little myself.

OK, strange, huh?

Here's my thinking - a little physics.

1

Newton's first law - equal and opposite reaction and all that jazz.

2

The energy that goes out the front of the muzzle (because of 1) is the same amount of energy that produces recoil. To reduce recoil, reduce energy. I think this is thermodynamics?

3

Kinetic energy = 1/2 x mass x velocity x velocity (v squared). Energy is affected more by velocity (square term) than by mass. 2x velocity gets 4x the energy while 2x the mass gets 2x the energy. We must get the velocity as low as possible to lower recoil.

4

Powerfactor fixes the relationship between mass and velocity (product must equal 170,000)

5

A 255gn SWC was the biggest I have tested (don't want to take up too much room in the case and sky the pressures)

6

a 255gn bullet can go 667fps (170000/255 = 667) and be legal, while a 230 needs to go 740, and a 200 needs to go 850fps.

7

Kinetic energy (in the metric system) expressed in Joules. When I crunch the numbers I get the 200gn generates 434,953 Joules, while the 255gn generates just 78% as much energy at 340,458 Joules.

I know you're saying "How can a heavier bullet produce less recoil?" the key is that energy (recoil) are affected more by velocity than by mass. Since the Powerfactor lets you lower the velocity by upping the mass, it works pretty cool.

I thought about the problem of shooting a bullet this slow. At the ranges you shoot in IDPA there is no important change in impact point. Also, my brass seems to last forever, less heat, less stress, less everything. You must adapt your shooting just a little because the bullet will impact higher on the target. I actually like this because the sites don't block out smaller targets (steel, thin sliver of shoot behind no shoot, etc).

Also the SWC puts big holes in the target. I can see them while firing (often quicker to take another shot than to take that -3). And I think it has helped a few "on-the-line" scores go my way.

Subjectively I do clearly feel a difference. I mixed the rounds in a mag (a buddy loaded them) and shot. I can 100% of the time pick out the 255gn and the (in my case 230gn).

I use bullets from national bullet co, but I'm going to try some from West Coast. Best thing to do is start low with a load and increase until the chrono gives you the right number (individual milage may vary)

Hope this helps (may confuse you!). Drop me a line if you want more info!

[Duane Thomas]

The consensus for decades has been that 200-gr. is the best bullet weight in .45 ACP. 185-grs. has to be pushed hard enough to make pf that it's a bit snappy. Heavier than 200-gr. and you get a bit too much muzzle flip. Of course, perception of recoil is such an individual thing, who can say that you might find any of these weights feels better or worse to you? I will say though, that when there's a general consensus there's usually a reason for that.

I'd definitely handload. True, a good shooter can still rock with a more heavily recoiling load, but you can shoot to a higher level more easily with lighter recoil. I'd suggest the Laser-Cast 200-gr. LSWC as a bullet. They're harder than the hinges of hell. I've fired over 15,0000 rounds of these things with zero leading. For a powder and charge weight, 4.7-gr. of Titegroup gives me a 170 pf from a 5" barrel. You'll want to chronograph, of course, to make sures that's true from your gun. Titegroup also has the advantage it's significantly less expensive than most other powders.

[D.Hayden]

Duane, I know this has been beat to death - but is there a big difference in lead vs Jacketed? Would you shoot a 200gr jacketed as well?

[Duane Thomas]

I'd expect so. The only real difference is that it requires a bit more powder to make the same pf with jacketed versus lead. More recoil, but not enough to really matter.

[Run n Gun]

Bit of a thread drift… sorry.

DT,

I too was a confirmed Laser-Cast user until my local supplier and I were out of bullets at the same time and in desperation I tried Burgess Bullets. They’re made right in your backyard, Moses Lake (509-762-4419). My gun guy said he tested them for hardness and they’re within 1bhn of Laser-Cast and they’re A LOT cheaper! In my gun the Burgess work superbly, 10yd 5 shot group that are easily completely covered by a nickel and NO leading. FWIW, YMMV.

Oh and Nick, I use the same load as Duane and I’m completely happy with it.

Ed

[Nick Weidhaas]

Thanks everyone for the input.

Gun Geek, your physics lesson was excellent (I wish I had paid more attention in school). Given your theory, if I did not want to shoot a lead bullet, a 230gr fmj loaded down to a 170pf would get me going in the right direction right?

S&B publish a velocity for their 230gr. fmj of 853fps at the muzzle and 829pfs at 25yards. Now if I use 840fps I get a pf of 193. Wow. So if I get some 230gr. fmj's and load them to a 170pf, I should see a difference, yes? Since I'm shooting the factory 230gr. ball Ok, a lighter 230gr. ball should allow me to control the gun a little better.

Duane and others. When I shot IPSC/USPSA 6-7+ years ago, I ran a 200gr. Hornady XTP for major competions from my Para P14 with good luck. I also realize that 200's have been the most popular choice. What Gun Geek gave me was the scientific explanation of what "should be" better, which is what I'm looking for. I know it is all subjective, but I think I'm going to give the 230's a try.

On a side note, I recently took an IDPA 2 day course from Steve Broom. Steve runs a company called Practical Shooting Institute and he is a top notch instr. Interestingly, he also recommended a 230gr. fmj bullet for CDP loaded at a 170pf.

If anyone has a load for a 230gr. fmj with Clays powder, Win. brass, and Win or Fed Primers, please let me know. As far as fmj bullets, Zero and Montana Gold seem to be the most popular. Any thoughts?

Thanks again,

Nick

[MoNsTeR]

I used 3.8gr of Clays with a 230RN for a while. Nice load but I have no idea what the PF is.

[tightloop]

To make major with a 230 you only have to drive it at 719fps. Why shoot one going at 850 if you don't have to.

I have shot lots rounds of 200 lsw in .45, first IPSC at 175 pf then into IDPA with 165 pf. They are avaliable, cheap, accurate, and work in most all guns. My choice.

[Gun Geek]

Nick:

I shoot plated bullets (Berry's, trying West Coast). They seem to work great and the perform more like jacketed bullets than lead, but they are cheaper.

[Norm Lee]

It turns out I have a pet theory, too, about recoil, both perceived and actual. Turns out I have pet theories about most things so it may be safe to quit reading about here.

I subscribe to that equal and opposite thing, too. I think that means that the momentum of the stuff going downrange is going to look like recoil in the uprange direction.

Heavier bullets should almost always produce lower recoil at a given power factor.

I think the energy thing really just affects the recoil signature ( and may have something to do with perceived recoil)

So why heavier bullets?

The stuff going downrange consists of a bullet of mass M going at a velocty V appropriate to the desired PF.

Along with the bullet are other ejecta, primarily a bunch of hot gas created by burning powder. So we have to add the powder (gas) momentum to get the total recoil MV + MpVp say.

So if we use less powder to get the PF we need, the recoil will be lower if all else is fixed. And so there is some advantage to using a heavy bullet over small charges of powder. Discretion is warranted since heavy bullets and fast powders is edgy territory.

The reason this works even though the differences in powder mass seem trivial is that the gasses are assumed to be travelling at a fairly rapid rate of Knots. Generally they are credited with moving at about 4000 fps. This makes the MpVp term significant.

Cheers,

Norm

Try 200 gr H&G 68 SWC over 4.5 V V N310

[2cats]

Loads I have used and like, and both make power factor from my GM:

230 gr West Coast RN, 1.255" x 0.469":

1) 5.1 gr Winchester 231

2) 7.0 gr AA#5

Lot's of people are able to make PF with 4.0 gr of Clays, and it's supposed to be real soft and very clean, but I had a terrible time with it; didn't work for me.

[underlug]

You want to use a round nose for your reloads

[Duane Thomas]

Why?

[DogmaDog]

Gun Geek,

Unfortunately, energy isn't the conserved quantity in your equations! The energy from the powder is NOT necessarily distributed equally to the gun and to the bullet, so kinetic energy is NOT the best proxy for recoil! (The energy is conserved, but it goes to making noise, moving the gun and shooter, moving the bullet, generating heat, and all kinds of stuff that you can't really keep track of.

What is the same is IMPULSE. A force acts on the bullet over a small period of time. The same force acts on the breechface of the gun for the same amount of time. Impulse is force x time, and is the same as momentum, which is mass times velocity, which is power factor. Power factor is therefore a better proxy for recoil. Using lighter bullets will require that they go faster, so they'll be in the barrel a shorter time, so the force must be greater. Lighter bullets will give you a "snappier" recoil. Heavy slow bullets spend longer in the barrel, so endure a smaller force over a longer time, resulting in a kind of "rolling" recoil. But the total impulse will be the same at a given power factor.

Now for some load data, since I shoot a .45 too.

180 gr. lead semi-wadcutter (actually 184 gr) w/5.1gr Winchester Super Target yields 930 fps/171 power factor

200 gr. LSWC (202 gr) w/4.6 gr WST yields 845 fps/171 PF

230 gr. LRN (227 gr) w/4.1 gr WST yields 743 fps/169 PF

230 gr. LRN (227 gr) w/4.3 gr WST yields 767 fps/174 PF

S&B 230 gr. FMJ chrono'd at 807 fps/185 PF

Typical Standard Deviation is about 3 PF for all loads.

All of these loads were shot from my gun and chronographed with a Pact Mk IV. Usual disclaimers denouncing any claim of similar or even safe results in YOUR gun apply.

Good luck,

DogmaDog

[Flexmoney]

Then there is the concept of forgetting what it feels like...and looking to the timer to see what works.

[tightloop]

Now, Flex

Let's not advocate something different than what you do, yourself. I'm not believing that you just load up whatever you have around the bench and if it makes major you shoot it, and disregard if it makes a 202PF instead of 170.

[MoNsTeR]

My own pet theory, in case in anyone is interested , is that the recoil perception has more to do with the burning characteristics of the powder charge than the weight of the bullet.

The general consensus is that for a given bullet and PF, a faster powder will generate less felt recoil. I believe this has to do somewhat with the mass of powder required, but more to do with the amount and pressure of the propellant gases at the time the bullet exits the muzzle. Slower burning powders generate a greater volume of gas which is at a higher pressure at bullet exit (as it is still burning). Absent a compensator to make good use of that gas, it increases felt recoil. Conversely, fast powders generate lower volumes of gas and when they exit the bore they are at a lower pressure as they are done burning.

As to bullet weight, the reason we see a correlation between soft-shooting loads and heavy bullets is because fast powders can often only make the desired power factor with heavier bullets. Or, if they can make PF with lighter bullets, you use too much powder and get an incomplete burn which eliminates the benefit of using a fast powder in the first place. I see it as no coincidence then that .45 shooters have a weaker preference for the heaviest bullets than .40 shooters. In .45, you can make PF with fast powders and your choice of 200's or 230's, or even 185's. Whereas in .40 with fast powders 135's and 165's are non-options; you must use 180's or 200's.

Or, I could just be full of it

[DogmaDog]

Monster,

Interesting. The momentum of the gas coming out of the muzzle does get balanced by momentum going into recoil of the gun. My guess would be that that momentum is insignificant compared to that of the bullet (I left it out in my discussion above for that reason), but maybe that assumption is wrong. In that case, slow burning powders would produce more momentum than faster burning powders even when the bullet momentum was the same, because more gas is leaving the muzzle at higher velocity.

I did find that shooting 180s at 170PF I felt pretty fast, like the gun was getting back on target more quickly than with heavier bullets. I don't know if that's true, though...no times to compare.

DD

[Flexmoney]

Now, Flex

Let's not advocate something different than what you do, yourself. I'm not believing that you just load up whatever you have around the bench and if it makes major you shoot it, and disregard if it makes a 202PF instead of 170.

Believe what you want...but, you shouldn't assume.

Perhaps you might want to re-read what I posted:

"...and looking to the timer to see what works."

The point I was trying to make is that the feel might be misleading. Some like to trade softness for a little snap.

Make sure to check the timer and see what gives the best results.

[tightloop]

If would not assume anything.

[Gun Geek]

Sorry for being MIA, been travelling for work. What a drag.

Dog:

You got me thinking a little, so I did some research.

First the thing about the momentum of the gas coming out of the barrel having some impact on the recoil. The answer is ABSOLUTELY. Recoil is comprised of 2 components; the impulse that you discussed as well as the ejection of the gas (same physics as a jet engine or a rocket motor). The momentum of the gas is why a compensator/muzzle brake works. It reduces the recoil and muzzle lift experienced by the shooter by redirecting some of the gas stream - Like the reverse thrusters on an airliner.

On the energy thing. I agree that KE is not really the thing that is conserved for just the reasons you said (heat, friction, sound, etc). It is, of course total energy that is conserved (1st law of thermo?). However, if you assume that those things are roughly equal when comparing 2 loads, you still get to the issue of lowering velocity lowers recoil more than mass. I didn't like that line of thinking so I looked a little harder (thank you Google!).

I found that there are several calculators on the web that will calc recoil energy. This one has some pretty cools stuff http://www.zvis.com/bali/bvjtools.shtml I used their formulas and set up a spreadsheet. The things you need to know are Bullet weight, Powder weight, Gun weight, and Muzzle Velocity.

Bullet Weight Velocity Recoil Energy

155 1129 13.21

185 945 12.79

200 875 12.37

230 760 11.96

255 686 11.45

These calcs show that using a heavier bullet (at lower velocity) will produce less recoil. I thought that these numbers were not really that different (11.5 up to 13.25) but as I looked at some other references, that really is a pretty big swing. High power rifles (30-06) will be in the 17 - 25 range and real butt kickers will be in the 30 - 40 range. Check out this link. http://www.chuckhawks.com/recoil_table_exp.htm. A 50BMG is about 95.

Again, the key is that with the heavier bullet you can go slower to meet powerfactor and this drops recoil faster than dropping mass.

Now I thought about another statement you made: "Impulse is force x time, and is the same as momentum, which is mass times velocity, which is power factor." It sounded reasonable to me but the analysis above contridicted it. I think the problem is in the units and the screwy issue of weight vs mass. I think in the english system we use something called ergs to represent mass. In the metric system it is of course grams. In the english system we use pounds, grains, ounces, for weight (force), in the metric system we use Newtons.

Power factor is given as weight in grains x velocity in ft/s. This is NOT mass x weight. Remember that F = ma (Newton's 2nd or 3rd?) or weight = mass x acceleration. Putting this into the PF formula you get PF = mass x accleration x velocity. When you work out the units this stuff you get a miss-match. In the metric system:

Momentum is mass x velocity = grams x (meters/seconds) = (gm)/s

Powerfactor is weight x velocity = (grams x (meters/second^2)) x meters/second = (gm^2)/s^3 (or gram-meters squared over seconds cubed).

So, I don't think powerfactor is the same as momentum

I don't mean to be disrepectful, and this is more than an academic discussion. Lowering recoil does lower my times in IDPA and IPSC shoots. If I'm out in left field, let me know, I'm always up for something that will improve my shooting.

Geek

[DogmaDog]

Gun Geek,

Cool site you posted!

On the "recoil energy calculator", it looks like they assume the velocity of gasses coming out of the muzzle is 4000fps, so you're right--the momentum of the propellant IS significant. I wonder how valid that constant is (don't you think a high pressure 9mm load would produce faster "exhaust gasses" than a low pressure .45?)

I have to disagree with your point about using weight vs. mass in the power factor equation. While it is true that grains is a measure of weight, while "slugs" is the english measure of mass (1 lb = 32 slug ft/s^2), it doesn't really matter--there is a 1 to 1, linear correlation between weight in grains and mass in slugs, so we can use "grains" as a proxy for mass as long as we don't get into any math that requires we make the distinction. You can put a bullet on your digital scale and press a button to see its weight in grains or mass in grams, for example (actually, digital scales measure weight, not mass, while balances measure mass, not weight). If you want to convert to "pound-seconds" or whatever people measure impulse with, then you may have to take that into account, but Power Factor is an arbitrary unit that will work.

The formula given on the site is: RI=(BM*BV+PC*CM)/g*mcoef

Recoil impulse equals (bullet mass*bullet velocity + powder mass*gas escape velocity)/g*7000. The 7000 converts grains to lbs, and the g (32 ft/s^2) converts the lbs to slugs. This is only important to be able to express the impulse as pound-seconds (mislabeled "lb/sec" on the site). The top part of the equation says it all: the recoil impulse is equal to the momentum of the bullet plus the momentum of the powder.

So if my 230 gr loading has a PF (momentum) of 169 (IPSC's weird arbitrary units), with 4.1gr of powder, and the powder really does exit the barrel at 4000fps, it adds an additional 4.1*4000/1000 = 16.4, for a total recoil impulse of 185.4power factor.

My 200 gr loading at PF 170 has 4.6 grains of powder =18.4 PF = 188.4 PF

My 180 gr load at PF 171 has 5.1 gr powder = 20.4 PF for a total of 191.4 PF

So, 1) sorry for the long discussion.

2) I think we can agree that heavier bullets are more efficient--regardless of the units of measure, you get less total recoil impulse for the same power factor using heavier bullets.

3) Here's the unsupported assertion: shooters can distinguish the character of a specific impulse--a large force for a short duration, or a smaller force for longer duration, each producing similar power factor (though the former situation is the less efficient). Shooters also change the way that impulse is transmitted to their hands by changing springs and lightening slides and heavy-ing (?) frames. The character of impulse which produces the fastest shot recovery/splits (or is "best feeling", depending on what you're after) will vary from shooter to shooter and will not follow a simple physical law.

Whew!

Thanks for the thought provoking discussion.

DD

[tightloop]

DD

Just don't try to tell the chrony folks that the powder should be included in the bullet weight calculation; I am afraid you'll get shut down..