MGM Spinners with 9MM

[D.Hayden]

I want to load up some heavier loads, for shooting the MGM Spinners in 3 Gun matches

I was thinking 147s loaded to a decent power factor

but 124s going faster have a higher foot-pounds calculation

What's the better indicator or 'power' to spin a spinner?

[outerlimits]

Dunno about spinners, but I can tell you from back in the bowling pin days, bigger bullets were always better.

[Yagi]

I've shot spinners on both 147 and 124 with my production gun... But i could honestly say that it doesn't matter within distance that is... What matters is timing and accuracy...

[Mbauer67]

I have worked up both 124 & 147 loads that were as hot as I could make them safely shoot out of a G34, and both have worked equally well. But I was able to achieve a slightly higher power factor with the 124's along with a bigger safety margin with regards to the powder charge weight varying slightly.

Basically what you are trying to do is work up towards a major powerfactor load, and shoot it out of a non-comped gun. CMJ'S worked best for me because they gave the longest OAL and greatest internal volume.

We all know that this is very dangerous and you must work up the load slowly. Because the gun your using makes a big difference.

[35WLN]

Have you shot a spinner with major 40 vs. your minor 9? The difference is maybe 1 but more likely 2 rounds. In my opinion your time and money is better spent on learning to be accurate faster and put multiple rounds ON the plates. Most of the time with major 3 on the top and then 4 on the bottom and then a finisher of 1 or 2 spins it.

[D.Hayden]

we have 5-7 spinners per match.. just looking for a better load out of a nine

Obviously.. hitting them is more important that what you're missing with

Just looking for what the has the higher power.. 124 faster, or a 147 at an equivalent power factor

I think I'll go with the 147s

[Alaskapopo]

I've shot spinners on both 147 and 124 with my production gun... But i could honestly say that it doesn't matter within distance that is... What matters is timing and accuracy...

I have found this too. A heavier load does help a little but what really matters is how fast you can hit it and the timing.

Pat

[njl]

AFAIK, for reactive targets, what really matters is momentum (m*v), not energy (m*v^2)/2.

So, look at your loads and pick the one with the higher power factor.

For a gross example:

124gr 9mm at 1100fps = 333 ft*lbs or 136pf

230gr .45 at 725fps = 268 ft*lbs or 166pf

If you've done any pin shooting, I think you already know which hits [much] harder. It's not the one with more energy.

[Religious Shooter]

I'd say go with the heavier bullets too. Same PF the heavier bullets always felt better to me.

That said... I use 115's for my main load and 124's for my "heavy" need to KTFO the target loads. The difference between POA and POI between my main 115 loads and my heavy 147 loads was very noticeable.

The extra power doesn't do me any good if I'm not hitting it.

[D.Hayden]

AFAIK, for reactive targets, what really matters is momentum (m*v), not energy (m*v^2)/2.

So, look at your loads and pick the one with the higher power factor.

For a gross example:

124gr 9mm at 1100fps = 333 ft*lbs or 136pf

230gr .45 at 725fps = 268 ft*lbs or 166pf

If you've done any pin shooting, I think you already know which hits [much] harder. It's not the one with more energy.

Nice.. thanks!

[MarkCO]

Impulse momentum, impact momentum, coefficient of restitution, plastic versus elastic deformation...Pins do not react the same as steel. Pins have a coupled plastic impact whereas steel has an elastic impact.

I did the calcs and shot a bunch of spinners and poppers using HS photography to try and measure the difference between 160s to 115s out of 9mms. The margin is thin, but with spinners, the 115 and 124 JHPs are a little better than anything else. Might it save you 1 round over the 147? maybe.

I use 124 JHP+P on spinners and have since had very little problems with them. I am spniing them in the same number of rounds with those as my major .40 loads. If the 147s shoot better for you, then use them over the 124s.

[D.Hayden]

Very cool Mark.. thanks

[njl]

Impulse momentum, impact momentum, coefficient of restitution, plastic versus elastic deformation...Pins do not react the same as steel. Pins have a coupled plastic impact whereas steel has an elastic impact.

I did the calcs and shot a bunch of spinners and poppers using HS photography to try and measure the difference between 160s to 115s out of 9mms. The margin is thin, but with spinners, the 115 and 124 JHPs are a little better than anything else. Might it save you 1 round over the 147? maybe.

I use 124 JHP+P on spinners and have since had very little problems with them. I am spniing them in the same number of rounds with those as my major .40 loads. If the 147s shoot better for you, then use them over the 124s.

I've done some spinner shooting too with 9mm, .40, and .45. With the first hand experience I have, I don't necessarily buy your explanation. What were the avg velocities of the various weight 9mm bullets you tested? Depending on how hot they're loaded a typical factory velocity 115gr could easily have more momentum than a soft loaded 147gr, and far more energy. What are the bullet types and velocities for your 9mm vs .40 loads?

Back when I had access to a spinner, I was shooting all factory ammo...and with a .45 (230gr Blazer, probably around 800fps), it only took a few hits to spin the spinner. With 115gr Blazer, it took many more hits. Muzzle energy is really close on these two rounds, but the .45 has way more momentum / pf (about 40% more).

Going back to the original question, keeping to 9mm, if all the various bullet weights are loaded to about the same PF (which is plausible), then sure, any one of them might do as well as another, because the difference in energy transferred to the target is going to depend more on bullet design (how the bullet interacts with the steel) than bullet mass because momentum will be about equal.

If the choice is any lead based 9mm vs just about any lead based .45, the heavier bullet is going to do better due to much higher momentum.

[MarkCO]

I was running velocities from 1000 fps with 160s up to 1400 fps with 115s. I was not using factory ammo, it was all carefully loaded and I was comparing equivalent energy loads in the 9mm vs. 40 as well as equivalent momentum and equivalent PF. Bullet diameter has an effect as well, but we are not talking about 9mm vs. .45, we are talking about 9mm vs. 9mm, so your example does not hold water in this specific case.

Your last sentence is correct when talking about things like bowling pins, but the bullet design and steel (even various types of steel) impact invalidates that assertion. Spinners do NOT act like pins, nor even plates or poppers depending on where and how they are hit. At an angle, the heavier slower bullet will not deliver the same percentage of it's energy as the faster lighter bullet, which gives the advantage (yes, slight) to the faster bullet given the same energy levels. The contact time with the target has an effect as does the deformation energy of the bullet. Granted, the differences are small, and hardly worth quibbling over. Like I said in my first post, shoot the one you shoot best, that is worth more than a slight.

[njl]

I was running velocities from 1000 fps with 160s up to 1400 fps with 115s. I was not using factory ammo, it was all carefully loaded and I was comparing equivalent energy loads in the 9mm vs. 40 as well as equivalent momentum and equivalent PF. Bullet diameter has an effect as well, but we are not talking about 9mm vs. .45, we are talking about 9mm vs. 9mm, so your example does not hold water in this specific case.

Those are both really hot loads, but a 115 at 1400fps actually has more momentum than a 160 at 1000fps...so based on momentum alone, I'd expect the 115 to be more effective on reactive targets.

[latech15]

the 147's are going to feel better as well. less recoil.

[njl]

the 147's are going to feel better as well. less recoil.

Loaded to the same PF, I agree...but that's another can of worms.