Felt recoil

[groundsclown]

Ok I know there's a lot of variables but bear with me while I try to explain what I've got going on/experienced.
These loads are from Lymans CB book.

45acp
200gr lead bullet
4.0gr bullseye (min 3.5gr)
fps 700'ish (est haven't chrono yet)
CUP 7,000 (est)
OAL 1.200

Same gun/bullet
4.5gr w231 (min 4.0)
fps 700'ish (again, est)
CUP 9-10,000 (est)
Same OAL

Both loads are extremely accurate with light/modest felt recoil.

Same gun/bullet
5.5gr Unique (min 5.0)
fps 700'ish (est)
CUP 7,500 to 8,500 (est)
Same OAL.

Felt recoil on this load was very hard. So much so that after only 7 rounds, I quit, took the remaining 18 home & pulled them thinking something went amiss. Charge was spot on at 5.5gr.
So I loaded another 10

5.0gr (min book load)
fps less than 700 (est)
CUP less than 8,000.

Felt recoil still seemed a lot harder than the BE or 231 loads, more than what I want (but less than the original 5.5gr load)

Which brings me to the question of...
If gun & bullet weight stay the same and FPS and CUP are within proximity, shouldn't felt recoil be close to the same?
I know Unique is slower than 231 or BE but with all else being relatively close to equal, shouldn't felt recoil also be equal?

 

[243winxb]

Alliant shows loads with there Speer 200 gr swaged lswc using 4.6 gr Bullseye- 807 fps. & 5.4 gr Unique - 790 fps. Your 4.0 gr of Bullseye would seem to be loaded lighter than a 5.5 gr Unique load. As you have found out.

 

[Reloadron]

Julian S. Hatcher put quite a bit of work into FRE (Free Recoil Energy) calculations which is covered in Hatcher's Notebook. The Lyman 49th Reloading Handbook, Appendix B, Page 454 shows pretty much the formula Hatcher derived. Been a few indepth threads on the subject here in the forums and there are a few online calculators that can be used to calculate FRE. Most seem to be based along the lines of the same formula.

The variables used are Bullet Weight, Powder Charge, Velocity and Weight of Gun. The end result is the Free Recoil Energy which is not "Felt Recoil". The problem with felt recoil is no two shooters will perceive recoil the same way even shooting the same loads in the same gun. Actual FRE also does not take into consideration factors like the grips on the gun or compensator and other features to reduce felt recoil.

Using the data for your loads in order they come up 3.20 FtLb, 3.29 FtLb, 3.49 FtLb and 3.39 FtLb respectively. So yes, your third load does in fact produce the greatest FRE. I based the numbers on a 1911 Frame weighing 2.5 Lbs.

Ron

 

[jmr40]

Anytime you use more powder recoil increases even if the velocity and bullet weight remain the same. Small increases in either bullet weight or velocity can make noticeable differences in recoil as well. You are just guessing on velocity too, a difference of 50 fps would be noticeable. And as said this is not felt recoil, but actual recoil since they are all fired from the same gun by the same shooter.

The same loads fired in a different gun with different grip shapes or grip angles will make a difference in how it feels.

 

[Reloadron]

For anyone curious as to how the variables affect the determination of Free Recoil Energy things look like this:

Free Recoil Energy (ft-lbs) = (((Bullet Weight in grains / 7000 * Velocity + Powder Charge in grains / 7000 * 4700)) ^2) / (Gun Weight in Pounds * 64.348)
Or
Free Recoil Energy (ft-lbs) = (W1 * Vp + 4700 * W2) ^2

Where:
• W1 = Weight of bullet in pounds (grains divided by 7000 equals pounds).
• W2 = Weight of powder charge in pounds.
• Wg = Weight of the gun in pounds
• Vp = Muzzle velocity of bullet in feet per second.
Example:
W1 for a 150 grain bullet = 150 divided by 7000 = .021
W2 for a 50 grain charge = 50 divided by 7000 = .007
Wg for a 9 pound rifle = 9
Vp for a velocity of 2700 fps = 2700
(.021 * 2700 + 4700 * .007) ^2 / 64.348 * 9
(56.7 + 32.9) ^2 / 579.132 = 13.86 ft-lbs

The above is based on the Lyman 49th Edition mentioned earlier. Keep in mind this yields a number that will be close to the FRE.

Ron

 

[ulflyer]

Try some Clays. I use both 231 and BE and like both, but out of curiosity after reading an advertisement that Clays was a "soft shooting powder", I tried it and never went back to anything else. Felt recoil was noticeably less. I shoot a 1991Al and load whatever it takes to reliably cycle the slide. This is on the low side of recommended grains. Also my shooting is simply for casual use.

 

[Jim Watson]

If you don't have actual velocities, just as well go by feel.
When you can get on a chronograph, you can determine whether computed recoil agrees with felt recoil.
Note that in a rifle, the powder charge is 1/3 to 1/2 the bullet weight and is assumed to blow past the bullet at high velocity for a significant "jet effect." A pistol with about 1/50 as much powder as lead is much less affected by the powder gas.

 

[Pete D.]

I own and use two .44 magnum pistols. One is a SBH with a 5.5 inch barrel. the other is a Thompson Contender with a 10 inch barrel.
I shoot the exact same loads in both. The Ruger (45oz.) is a great fun to shoot. The Contender (52oz) is no fun at all. It is a scope breaker. According to the formulas, there is about a 2ft.lb increase in free recoil with the T/C due to increased velocity. It sure feels like more than that.

 

[Reloadron]

I own and use two .44 magnum pistols. One is a SBH with a 5.5 inch barrel. the other is a Thompson Contender with a 10 inch barrel.
I shoot the exact same loads in both. The Ruger (45oz.) is a great fun to shoot. The Contender (52oz) is no fun at all. It is a scope breaker. According to the formulas, there is about a 2ft.lb increase in free recoil with the T/C due to increased velocity. It sure feels like more than that.

A 44 Magnu revolver I have enjoyed for years is my S&W Model 29-5 with an unfluted cylinder. When I got that gun it came with the beautiful S&W N Frame wood grips. I kept my original grips and replaced them with a S&W Pachmeyer soft rubber grip. Obviously the gun weight didn't change much if any at all. However, the shock absorbing properties of those rubber grips make the gun much, much more enjoyable to shoot. Now if I work the FRE numbers the recoil has not changed but the actual felt recoil has changed significantly. Believe me it has changed.

There is actually some pretty interesting material out there on the subject of FRE and I read a few white papers done by college students who built test stands to measure FRE using today's sensors. Much like measuring actual chamber pressures things have come a long way. This particular senior project I found interesting. Especially considering they went to Weatherby and presented their ideas to get some gun support. Anyway, the entire recoil energy thing can get interesting, especially the changes since Hatcher published so much data on the subject.

Ron

 

[Grumulkin]

I own and use two .44 magnum pistols. One is a SBH with a 5.5 inch barrel. the other is a Thompson Contender with a 10 inch barrel.
I shoot the exact same loads in both. The Ruger (45oz.) is a great fun to shoot. The Contender (52oz) is no fun at all. It is a scope breaker. According to the formulas, there is about a 2ft.lb increase in free recoil with the T/C due to increased velocity. It sure feels like more than that.

I think the biggest issue in the Contender is the design of the grip.