Home Forums Classifieds Blogs Today's Posts Search Social Groups



  
SIGN-UP
Notices

Glock Talk
Welcome To The Glock Talk Forums.

 
  
Reply
 
Thread Tools Display Modes
Old 10-01-2010, 20:14   #1
greenlion
Senior Member
 
greenlion's Avatar
 
Join Date: Jul 2009
Location: North Carolina
Posts: 929
10mm / 40 S&W pressure difference

A while back I made a comment on someone else's post stating that I thought the 10mm had less felt recoil than the .40 S&W, given the same bullet weight and velocity. Everyone seemed to chalk it up to the extra size and weight of the GLOCK 20sf. At the time, I stated that I thought the pressures would also be less in the downloaded 10mm because of the increased case capacity. Everyone seemed to disagree with that idea.

However, I was just comparing the .40 and 10mm load data on the Hodgdon reloading website, and there is indeed as much as a 5,000 psi pressure difference between the .40 and 10mm given the same bullet at the same velocity.

Example:
.40 S&W 155gr Hornady XTP @ 1030 fps = 28,100 psi
10mm 155gr Hornady XTP @ 1030 fps = 23,000 psi

I don't see how this could not effect felt recoil.
greenlion is offline   Reply With Quote
Old 10-02-2010, 00:54   #2
Glolt20-91
Senior Member
 
Glolt20-91's Avatar
 
Join Date: Jul 2005
Location: Arizona Territory
Posts: 5,732
Chamber pressure doesn't relate to recoil.

Bullet weight, bullet velocity, firearm weight and powder weight are all I need to determine recoil using RCBS software.

Here's some recoil comparisons I've posted in the past with some powder manipulation;

Colt 1911 Gov't;

Quote:
230gr Golden Saber 990fps, 10.0gr Blue Dot,
Recoil = 9.82ft/lbs, 16.10fps (13.35fps bullet – 2.75fps powder)

Testing with Power Pistol, reduced muzzle blast and recoil, ejected brass fell closer to the shooter because of reduced slide speed, but how would it chrono?

230gr Gold Dot 984fps, 7.3grs Power Pistol – load carry for two Colts,
Recoil = 8.8ft/lbs, 15.1fps. (13.2fps bullet, 1.9fps powder)

This loading is closer to some of the upper end standard factory loadings and proved to be the most accurate in searching for a common powder for four 1911 .45acp barrels;

230gr Golden Saber 890fps/501fpe, 6.0grs Universal Clays,
Recoil = 7.06ft/lbs, 13.65fps.
Now compare an upper end 10mm load from a G20;

Quote:
Since the 10mm is often compared to the .357mag, here’s some recoil data with a G20/6”, 29oz, (Fully supported KKM barrel, not Glock)
165gr Golden Saber, 1402fps/720fpe, AA #7 – 12.0grs;
Recoil = 14.46ft/lbs, 22.7fps (18.21fps bullet, 4.45fps powder).
Now the numbers from a 6" M686 that approximates bullet weight and velocity;

Quote:
158gr Winchester notched JHP, 1440fps/727fpe, 14.8grs AA #9,
Recoil = 10.49ft/lbs, 15.84fps (12.09fps bullet, 3.75fps bullet)
My Steyr M40-A1 has less muzzle flip than a G22 shooting the same ammo, probably because of its ergonomics.

A high chamber pressure .40 S&W 165gr Gold Dot load ballparking the above 10mm chamber pressure;

Steyr M40-A1, 4" with fully supported chamber, do not use this load in a Glock/unsupported barrel. This is a very stout load using Vihtavuori #4 manual data;

Quote:
Steyr M40-A1, 4”, 27.0oz empty
165gr Gold Dot, 1236fps/539fpe, Vihtavuori 3N38 – 9.8grs.
Recoil = 11.75 ft/lbs, 21.2fps (17.2fps bullet, 4.0fps powder)
Even though both the .40S&W and 10mm were loaded near their upper pressure limits, the 10mm recoils more due to its faster MV and increased powder weight.

Now we can take this data one step further, while I don't know the powder weights/type used in Double Tap ammo; here's DT's ballistic gel data with 4-layers of denim that ballparks the above data used to determine recoil;

Quote:
DoubleTap .40 S&W Penetration / expansion
165gr Gold Dot JHP @ 1200fps - 14.0" / .70"

DoubleTap .357 Magnum
158gr. Gold Dot JHP @ 1400fps - 19.0" .56"

DoubleTap 10mm
165gr Golden Saber JHP @ 1425fps - 14.75" / .82"

DoubleTap .45ACP
230gr Gold Dot JHP @ 1010fps - 15.25" / .95"
Hopefully this will give you some added insight into the recoil/bullet performance relationships.

Bob
__________________
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity."
- General George S. Patton, Jr

"Speed is fine, but accuracy is final - Bill Jordan

Last edited by Glolt20-91; 10-02-2010 at 00:55..
Glolt20-91 is online now   Reply With Quote
Old 10-02-2010, 02:01   #3
fredj338
Senior Member
 
fredj338's Avatar
 
Join Date: Dec 2004
Location: so.cal.
Posts: 21,748
Blog Entries: 3
Quote:
Originally Posted by greenlion View Post
A while back I made a comment on someone else's post stating that I thought the 10mm had less felt recoil than the .40 S&W, given the same bullet weight and velocity. Everyone seemed to chalk it up to the extra size and weight of the GLOCK 20sf. At the time, I stated that I thought the pressures would also be less in the downloaded 10mm because of the increased case capacity. Everyone seemed to disagree with that idea.

However, I was just comparing the .40 and 10mm load data on the Hodgdon reloading website, and there is indeed as much as a 5,000 psi pressure difference between the .40 and 10mm given the same bullet at the same velocity.

Example:
.40 S&W 155gr Hornady XTP @ 1030 fps = 28,100 psi
10mm 155gr Hornady XTP @ 1030 fps = 23,000 psi

I don't see how this could not effect felt recoil.
In your example, the recoil impulse would be indetical in identical guns. The issue, most 10mm are heavier than 40s. The only diff possible, what powder was used in each to get that vel. I could easily build a load that KBs a 40 w/ less powder & less vel than the 10mm. Maybe a dbl. charge of TG & 180gr bullet, maybe 50Kpsi @ 1100fps? POW!
__________________
"Given adequate penetration, a larger diameter bullet will have an edge in wounding effectiveness. It will damage a blood vessel the smaller projectile barely misses. The larger permanent cavity may lead to faster blood loss. Although such an edge clearly exists, its significance cannot be quantified".

Last edited by fredj338; 10-02-2010 at 02:03..
fredj338 is offline   Reply With Quote
Old 10-02-2010, 07:19   #4
greenlion
Senior Member
 
greenlion's Avatar
 
Join Date: Jul 2009
Location: North Carolina
Posts: 929
Glolt20, I understand that there will be recoil differences between different bullet weights and velocities. That much is obvious. I was comparing apples to apples, with the only variable being pressure.

I guess I do see what you guys are saying. While the higher pressure is more wearing on the gun, it does not factor into the physics of the recoil impulse. In the world of felt experience though, it seems like SUCH a different (snappy) impulse from a .40 than it does a in a downloaded 10mm, that it doesn't seem like it could just be the slight increase in gun size causing it.
greenlion is offline   Reply With Quote
Old 10-02-2010, 10:16   #5
Glolt20-91
Senior Member
 
Glolt20-91's Avatar
 
Join Date: Jul 2005
Location: Arizona Territory
Posts: 5,732
Quote:
Originally Posted by greenlion View Post
Glolt20, I understand that there will be recoil differences between different bullet weights and velocities. That much is obvious. I was comparing apples to apples, with the only variable being pressure.

I guess I do see what you guys are saying. While the higher pressure is more wearing on the gun, it does not factor into the physics of the recoil impulse. In the world of felt experience though, it seems like SUCH a different (snappy) impulse from a .40 than it does a in a downloaded 10mm, that it doesn't seem like it could just be the slight increase in gun size causing it.
I understand, just trying to share raw data from loads I've personally chronographed and ran recoil software on.

Here's some data from testing I did years ago and posted on GT, G20 (28oz) and a Steyr M40-A1 (27oz) heads up with 155gr Gold Dots. This is as close as I can get comparing 10mm and .40S&W pistol weights, the Steyr is very robust in its construction.

G20, 12.0grs Blue Dot at 1242fps
Recoil:
11.21ft/lbs, 20.3fps (15.69fps bullet - 4.60fps powder)

Steyr M40-A1, 7.8grs Unique at 1279fps
Recoil:
10.47ft/lbs, 19.98fps (16.81fps bullet - 3.18fps powder)

Both of these loads operate at upper level SAAMI pressures according to Speer - 37,500psi 10mm (12.0gr Blue Dot) and 35,000psi .40S&W (8.0gr Unique)

Both of these loads were chronographed on the same day and is as close as I can get heads up to your requirements.

In this particular test, the .40 Gold Dot achieved faster velocity from a shorter barrel, with less recoil and assuming less chamber pressure.

The Steyr can put up some very fast split times compared to the G20.

Bob
__________________
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity."
- General George S. Patton, Jr

"Speed is fine, but accuracy is final - Bill Jordan

Last edited by Glolt20-91; 10-02-2010 at 10:24..
Glolt20-91 is online now   Reply With Quote
Old 10-02-2010, 11:45   #6
fredj338
Senior Member
 
fredj338's Avatar
 
Join Date: Dec 2004
Location: so.cal.
Posts: 21,748
Blog Entries: 3
Quote:
Originally Posted by greenlion View Post
Glolt20, I understand that there will be recoil differences between different bullet weights and velocities. That much is obvious. I was comparing apples to apples, with the only variable being pressure.

I guess I do see what you guys are saying. While the higher pressure is more wearing on the gun, it does not factor into the physics of the recoil impulse. In the world of felt experience though, it seems like SUCH a different (snappy) impulse from a .40 than it does a in a downloaded 10mm, that it doesn't seem like it could just be the slight increase in gun size causing it.
Every ounce of gun wt in a handgun significantly reduces recoil impulse. The same ammo in a 4oz heavier gun is just gonna shoot softer, there is no way around that. The converse is true. Stuff 155gr 40s in a G27 & then into a G20 w/ after market bbl. The recoil impulse diff is dramatic.
__________________
"Given adequate penetration, a larger diameter bullet will have an edge in wounding effectiveness. It will damage a blood vessel the smaller projectile barely misses. The larger permanent cavity may lead to faster blood loss. Although such an edge clearly exists, its significance cannot be quantified".

Last edited by fredj338; 10-02-2010 at 11:45..
fredj338 is offline   Reply With Quote
Old 10-02-2010, 13:39   #7
cowboy1964
Senior Member
 
Join Date: Sep 2009
Location: U.S.A.
Posts: 15,063
Doesn't lower pressure "spread out" the impulse, resulting in a perception of lower overall recoil/flip/torque? The 45 ACP is the prime example.
cowboy1964 is offline   Reply With Quote
Old 10-02-2010, 13:53   #8
fredj338
Senior Member
 
fredj338's Avatar
 
Join Date: Dec 2004
Location: so.cal.
Posts: 21,748
Blog Entries: 3
Quote:
Originally Posted by cowboy1964 View Post
Doesn't lower pressure "spread out" the impulse, resulting in a perception of lower overall recoil/flip/torque? The 45 ACP is the prime example.
Slightly, very slighty, most would never know it. Run a 185gr 45acp @ 1150fps, feels just like a 10mm w/ 180gr @ 1200fps w/ 10K less pressure.
__________________
"Given adequate penetration, a larger diameter bullet will have an edge in wounding effectiveness. It will damage a blood vessel the smaller projectile barely misses. The larger permanent cavity may lead to faster blood loss. Although such an edge clearly exists, its significance cannot be quantified".

Last edited by fredj338; 10-02-2010 at 13:53..
fredj338 is offline   Reply With Quote
Old 10-02-2010, 14:51   #9
Glolt20-91
Senior Member
 
Glolt20-91's Avatar
 
Join Date: Jul 2005
Location: Arizona Territory
Posts: 5,732
Quote:
Originally Posted by fredj338 View Post
Every ounce of gun wt in a handgun significantly reduces recoil impulse. The same ammo in a 4oz heavier gun is just gonna shoot softer, there is no way around that. The converse is true. Stuff 155gr 40s in a G27 & then into a G20 w/ after market bbl. The recoil impulse diff is dramatic.
If I was able to get the .40S&W/155gr GD velocity out of a 21oz G23; recoil jumps to ~13.5 ft/lbs, significantly higher than the G20 or Steyr.

Bob
__________________
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity."
- General George S. Patton, Jr

"Speed is fine, but accuracy is final - Bill Jordan
Glolt20-91 is online now   Reply With Quote
Old 10-02-2010, 16:04   #10
English
Senior Member
 
Join Date: Dec 2005
Location: London
Posts: 5,583
Quote:
Originally Posted by greenlion View Post
A while back I made a comment on someone else's post stating that I thought the 10mm had less felt recoil than the .40 S&W, given the same bullet weight and velocity. Everyone seemed to chalk it up to the extra size and weight of the GLOCK 20sf. At the time, I stated that I thought the pressures would also be less in the downloaded 10mm because of the increased case capacity. Everyone seemed to disagree with that idea.

However, I was just comparing the .40 and 10mm load data on the Hodgdon reloading website, and there is indeed as much as a 5,000 psi pressure difference between the .40 and 10mm given the same bullet at the same velocity.

Example:
.40 S&W 155gr Hornady XTP @ 1030 fps = 28,100 psi
10mm 155gr Hornady XTP @ 1030 fps = 23,000 psi

I don't see how this could not effect felt recoil.
You were quite correct that the 10mm will have a lower quoted pressure to achieve the same velocity as a .40S&W. You are also correct that the reason for this is the extra space in the 10mm case.

The important thing you are missing is that the quoted pressure is the peak pressure. That occurs quite soon after the bullet leaves the chamber when the space behind the bullet is low. As the bullet gets further down the barrel the space in the cartridge becomes less important as it becomes a smaller proportion of the whole.

The 10mm gets to the same velocity because the pressure down much of the rest of the barrel is higher, but this can happen only if the 10mm has more propellant. It can carry more propellant safely because of that extra space in the case but the cost is that the bullet does not get that initial high acceleration of the smaller case .40S&W with a lower charge. Rifle shooter talk of efficient cartridges that use less powder to get the same velocity but, as with the 10mm and 40S&W, they are talking of less than maximum loads in the less efficient cartridge.

The knock on effect of this is that for such loads the 10mm will have more recoil because a greater mass of gas is jetting out of the muzzle at an average speed around 2,500 or 3,000 fps.

Especially for an auto pistol, the pressures at different points along the bullets position in the barrel don't make any difference to the recoil. All you need conceren yourself with is the bullet mass and velocity and the powder mass. That gives you the total ejecta momentum and hence the total gun momentum.

The reason you feel that the .40S&W kicks so much harder is because it is a lighter pistol and felt recoil is not a linear matter. That is, 10% more recoil velocity can feel like a lot more than 10% more recoil. In this case the G22 is 25.67oz with magazine and the G20 is 30.32oz or 18.1% more. So the recoil velocity of the G20 would be about 15.3% less for the same ejecta momentum. As we have seen, that is not equivalent to the bullet momentum so the real figure would be a little less - say about 13% instead of 15.3%. That 13% can take you over the edge from comfortable to uncomfortable.

English
English is offline   Reply With Quote
Old 10-02-2010, 16:17   #11
greenlion
Senior Member
 
greenlion's Avatar
 
Join Date: Jul 2009
Location: North Carolina
Posts: 929
Quote:
Originally Posted by cowboy1964 View Post
Doesn't lower pressure "spread out" the impulse, resulting in a perception of lower overall recoil/flip/torque? The 45 ACP is the prime example.
This is what I'm talking about. That is what it feels like. A completely different impulse.

I've shot .40 out of a 22, 23, and 27 and I know there is a bit of difference between those models due to weight and length of barrel, but this is different. All those still feel like you are shooting the snappy little .40 round. The downloaded 10mm feels like a different, more pleasant round to shoot.
greenlion is offline   Reply With Quote
Old 10-02-2010, 20:23   #12
Glolt20-91
Senior Member
 
Glolt20-91's Avatar
 
Join Date: Jul 2005
Location: Arizona Territory
Posts: 5,732
Quote:
Originally Posted by cowboy1964 View Post
Doesn't lower pressure "spread out" the impulse, resulting in a perception of lower overall recoil/flip/torque? The 45 ACP is the prime example.
Let's run the numbers and see. I went back in my reload notes 5 years and came up with some upper end .45/185gr and 10mm/180gr pressure loads at the same MV.

Keep in mind that the .45auto casing will hold about 3.0 grains more water than the 10mm case.

I'm going to ballpark ~21,000-23,000psi for the .45auto and between 30,000-35,000psi for the 10mm. I used a faster burning powder in the 10mm in order to achieve a relatively low MV at high pressure.

While MVs are nearly identical, the extreme spread of the .45auto is slightly more.

Let's assume a 10mm barrel in a G21 to keep the weight also constant.

Data:
M1991 Colt Lew Horton combat/target, 5" barrel, 185gr Golden Saber, 8.2grs Unique, this is max powder weight from Speer;

1126fps, ES 58fps, SD 20fps.

Glock 20, 4.6", 180gr Sierra JHP, 6.3grs Universal Clays, 6.4grs is max powder weight from Sierra V;

1122fps, ES 37fps, SD 11fps.

Doesn't matter if the Glock weight is 28oz or 38oz, the low pressure .45auto will have slightly more recoil because it needs more powder to launch a bullet to the same MV.

Clearly, chamber pressure is not relevant to recoil in this comparison.

Arbitrarily picking 30oz pistol weight.

.45/185 Recoil;
10.29ft/lbs, 18.79fps (15.93fps bullet - 2.86fps powder)

10mm/180gr recoil;
8.94ft/lbs, 17.51fps (15.36fps bullet - 2.15fps powder)

Bob
__________________
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity."
- General George S. Patton, Jr

"Speed is fine, but accuracy is final - Bill Jordan

Last edited by Glolt20-91; 10-02-2010 at 20:26..
Glolt20-91 is online now   Reply With Quote
Old 10-04-2010, 07:12   #13
English
Senior Member
 
Join Date: Dec 2005
Location: London
Posts: 5,583
Quote:
Originally Posted by greenlion View Post
This is what I'm talking about. That is what it feels like. A completely different impulse.

I've shot .40 out of a 22, 23, and 27 and I know there is a bit of difference between those models due to weight and length of barrel, but this is different. All those still feel like you are shooting the snappy little .40 round. The downloaded 10mm feels like a different, more pleasant round to shoot.
The pressure variations in the barrel all happen before the barrel has unlocked from the slide and so the changes in momentum happen only against the resistance of the recoil spring during the very first part of its compression. As a result you cannot feel these variations and only feel the toatal recoil momentum as recoil spring compression and the impacts of the barrel on the locking block and the slide hitting the frame at the end of its travel. The perceived snappiness of the .40 is entirely a matter of the light weight of the pistol and the relatively light weight of the slide relative to the slides of the .45ACP, 10mm and .45GAP pistols.

English
English is offline   Reply With Quote
Old 10-04-2010, 07:37   #14
cowboy1964
Senior Member
 
Join Date: Sep 2009
Location: U.S.A.
Posts: 15,063
Quote:
Originally Posted by English View Post
The perceived snappiness of the .40 is entirely a matter of the light weight of the pistol and the relatively light weight of the slide relative to the slides of the .45ACP, 10mm and .45GAP pistols.
A Glock 36 weighs almost exactly the same as a Glock 27. I bet most people would say the 27 has more "snap" though the 36 may have more overall recoil.
cowboy1964 is offline   Reply With Quote

 
  
Reply


Tags
.40 s&w, 10mm, pressure, recoil
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump




All times are GMT -6. The time now is 12:10.




Homepage
FAQ
Forums
Calendar
Advertise
Gallery
GT Wiki
GT Blogs
Social Groups
Classifieds


Users Currently Online: 1,209
302 Members
907 Guests

Most users ever online: 2,672
Aug 11, 2014 at 2:31