Pressure Vs. Recoil feel

[Shay1911]

Two rounds

9mm

Identical bullet weight

Identical powder

Identical Power Factor

Slightly less powder load in Bullet 2

Round 1 is loaded long, on the low pressure side (1.16 OAL)

Round 2 is loaded short, on the high end of SAAMI pressure side (1.08 OAL)

Even though they have same power factor, would round 2 be snappier and round 1 be softer?

[HSMITH]

Depends, a very fast powder probably won't have much if any difference in feel. A slower powder will maintain more pressure as the bullet exits in both cases and the short load might push more. Using the same powder at the same power factor varying only OAL it is going to be VERY difficult to tell the difference, maybe impossible.

Do the experiment and let us know what you felt.

[Shay1911]

This is all subjective of course and I can't think of a way to actually measure it...

When I was loading long, even though I was making power factor, people were commenting about my "mouse flatulence" loads. With the shorter loads, I feel it is much snappier and harder for me to keep sights on target. They have a lot more pop to them.

I compared a faster power, Ramshot Comp, with Ramshort Sil. Both loaded to same length and same power factor, I did not notice a difference in recoil or snappiness. The Ramshot Sil was much more accurate for me. These were 147 loads.

I also loaded some 124's with Ramshot Comp, same power factor and length and I think they felt just as soft as the 147 Ramshot Sil, if not softer.

This is all subjective, just wanted to confirm with others.

[Joseph796]

This is all subjective of course and I can't think of a way to actually measure it...

When I was loading long, even though I was making power factor, people were commenting about my "mouse flatulence" loads. With the shorter loads, I feel it is much snappier and harder for me to keep sights on target. They have a lot more pop to them.

I compared a faster power, Ramshot Comp, with Ramshort Sil. Both loaded to same length and same power factor, I did not notice a difference in recoil or snappiness. The Ramshot Sil was much more accurate for me. These were 147 loads.

I also loaded some 124's with Ramshot Comp, same power factor and length and I think they felt just as soft as the 147 Ramshot Sil, if not softer.

This is all subjective, just wanted to confirm with others.

Shay,

Did you ever try Ramshot True Blue? True blue is slower than Silhoutte. If not, let me know & I will provide some to experiment. I am going to start reloading 9mm for Production Class.

Are you shooting Sunday?

Randy

[Allgoodhits]

Two rounds

9mm

Identical bullet weight

Identical powder

Identical Power Factor

Slightly less powder load in Bullet 2

Round 1 is loaded long, on the low pressure side (1.16 OAL)

Round 2 is loaded short, on the high end of SAAMI pressure side (1.08 OAL)

Even though they have same power factor, would round 2 be snappier and round 1 be softer?

The scientific answer is: http://www.handloads.com/calc/recoil.asp

Martin

[Shay1911]

Hey Randy,

I will see you Sunday:) Thanks for the offer.

I gather that the faster the powder is the softer the recoil.

My question is really about the length of the cartridge and how it affects speed of recoil.

I found this calculator: http://kwk.us/powley.html

Which helps with estimating pressure. Not sure how accurate it is though.

Welcome to Production by the way, I am moving to Limited next week:)

Thanks,

Shay

[pevadijk]

I think I have some info on this, as I have been playing with the chrono yesterday!

Since My 9mm Edge works best with long rounds and my buddy shoots short ammo in his CZ, I thought I should use some of his rounds in my gun and the difference was quite noticeable.

Using 4,0 grain of N320 with 124grain Berry's bullets, I got this:

COL 27,7mm: average speed=1037fps

COL 29,75mm: average speed=970 fps

So I guess it's safe to say that a longer COL leads to more room in the case and lower pressures, thus lower speeds.

BTW, I achive higher velocities with N340, but I like the snappy feel of N320, although it's harder to make minor (yes, that sounds funny), while staying within Vihta's loading tables.

Edited December 29, 2007 by pevadijk

[G-ManBart]

Two rounds

9mm

Identical bullet weight

Identical powder

Identical Power Factor

Slightly less powder load in Bullet 2

Round 1 is loaded long, on the low pressure side (1.16 OAL)

Round 2 is loaded short, on the high end of SAAMI pressure side (1.08 OAL)

Even though they have same power factor, would round 2 be snappier and round 1 be softer?

I'm certainly not a world-expert when it comes to ballistics, but I think you're overlooking something here.

If you have slightly more powder and a longer OAL in #1 and slightly less powder and shorter OAL in #2 you should be getting the same pressure level.

If it's the same bullet and same powder you need the same pressure to get identical velocity...at least it's going to be so close to identical that individual variation between loaded rounds would make it almost impossible to measure any difference.

[19852]

Shay,

I am also set to run some experiments with VVN320 vs the N340 I had been using. Just before my press broke I had 4.1 gr. N320 behind a Montana Gold 124, just made Pf at 1039fps in my CZ 75 but shot 2-3" low at 25 yrds. My fixed sight were a-ok with 4.7 N340 behind a Zero 125JHP. I now have some 124 MG's with 4.2, 4.3 and 4.4 gr N320, hoping to raise my POI w/o to much recoil penalty, does this seem like a sound idea? I also have some Ramshot comp, what were you using with the 124gr. load with this powder? I can't seem to find much data on this powder.

Thank you

[G-ManBart]

Shay,

I am also set to run some experiments with VVN320 vs the N340 I had been using. Just before my press broke I had 4.1 gr. N320 behind a Montana Gold 124, just made Pf at 1039fps in my CZ 75 but shot 2-3" low at 25 yrds. My fixed sight were a-ok with 4.7 N340 behind a Zero 125JHP. I now have some 124 MG's with 4.2, 4.3 and 4.4 gr N320, hoping to raise my POI w/o to much recoil penalty, does this seem like a sound idea? I also have some Ramshot comp, what were you using with the 124gr. load with this powder? I can't seem to find much data on this powder.

Thank you

It depends on the distance where your gun hits to point of aim, but in many cases higher velocity will give you a lower point of impact. The bullet leaves the barrel sooner in the recoil movement so it's launched at a lower angle than a slower bullet. The only way to tell is to try and see what happens.

[Shay1911]

Here is what I found...

I took 100 rounds of each to the range and shot fast groups with them.

147 Precision 4.0 Ramshot Sil

147 Precision 3.1 Ramshot Comp

124 FMJ 4.0 VV N320

124 FMJ 3.9 Ramshot Comp

124 FMJ 4.9 Ramshot Sil

The CZ has a very fast slide. The 147 rounds were almost always down and left. I figured with the very low PF, they leave the barrel when it is already moving, making an inaccurate round.

The 124's were right on, very tight groups, very accurate. The sights always came back quickly.

I didnt notice any difference between the Ramshot Comp and the VV N320, but I didnt like the Ramshot Sil as much.

The load I settled on was 124 FMJ, 3.9 Ramshot Comp at 1.082 OAL.

The 147 may work for others and maybe other guns, but I liked the 124's. I should have listened to Angus a while back, that's what he told me to do.

[19852]

I did my unscientific tests today at the range, 70's and sunny, this is Florida. VV N320, Montana Gold 124FMJ @ 4.2, 4.3 and 4.4 grs. all of these at my old longer OAL of 1.12. Plus some with 4.2gr at 1.085 OAL. It is my opinion that the 4.3 @ 1.12 and the 4.2 @ 1.085 were most alike in recoil feel, POI and group size. I am going to load up some more at 1.085 with 4.2 N320 for more testing. I am also going to try the Ramshot comp with 3.9 grs.