GlockTalk.com
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 08-21-2013, 10:16   #21
GRT45
Transform & Win
 
GRT45's Avatar
 
Join Date: Jun 2010
Location: Texas
Posts: 2,914
Quote:
Originally Posted by nraman View Post
I read that the G20 slide weighs more than the G21, that would give it more inertia.
Yep, there is a small difference in mass between the two slides. The G20 and G21 slide shared a common origin in design and use the same RSA, but some mass was removed from the G21 slide to tune it for the smaller recoil impulse of the lower energy 45ACP round.

Below is a photo comparison of the factory G20 10mm slide (left) and factory G21 45ACP slide (right). The muzzle end of the slides are at the bottom of the photo. Note the milled areas in the interior on both sides of the G21 slide that removes non-structural mass forward of the chamber opening.

General Glocking
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
: Strictly monogamous, I have one Glock and one woman.
GLOCK Certified Armorer,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Member,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Endowment Member, Eagle Scout

Last edited by GRT45; 08-31-2013 at 09:41..
GRT45 is offline   Reply With Quote
Old 08-21-2013, 17:08   #22
VBVAGUY
Member
 
Join Date: Mar 2010
Posts: 17
Wow interesting information here !!! Thanks for sharing !!! God Bless
VBVAGUY is offline   Reply With Quote
Old 08-21-2013, 19:10   #23
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by GRT45 View Post
Yep, there is a small difference in mass between the two slides. The G20 and G21 slide shared a common origin in design, but some mass was removed from the G21 slide to tune it for the smaller recoil impulse of the lower energy 45ACP round.

Below is a photo comparison of the factory G20 10mm slide (left) and factory G21 45ACP slide (right). The muzzle end of the slides are at the bottom of the photo. Note the milled areas in the interior on both sides of the G21 slide that removes non-structural mass forward of the chamber opening.

General Glocking
Man. If I want to modify my G21SF to shoot .45 Super and .40 Super I hope the G21 slide can handle those pressures. You may know, .40 Super surpasses 10mm velocities and muzzle energy.
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC
Roger G23 is offline   Reply With Quote
Old 08-21-2013, 20:18   #24
cciman
Senior Member
 
cciman's Avatar
 
Join Date: Jan 2009
Location: SW Ohio
Posts: 2,469
The barrel matters, the slide less so. Slide does not actually experience any "pressures" but takes on the kinetic energy. Choosing the correct spring, breachface and extractor geometry as you alluded to, needs to happen.

Quote:
Originally Posted by Roger G23 View Post
Man. If I want to modify my G21SF to shoot .45 Super and .40 Super I hope the G21 slide can handle those pressures. You may know, .40 Super surpasses 10mm velocities and muzzle energy.
cciman is offline   Reply With Quote
Old 08-21-2013, 20:33   #25
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by cciman View Post
The barrel matters, the slide less so. Slide does not actually experience any "pressures" but takes on the kinetic energy. Choosing the correct spring, breachface and extractor geometry as you alluded to, needs to happen.
Thank you sir. I appreciate that very much.
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC
Roger G23 is offline   Reply With Quote
Old 08-21-2013, 20:36   #26
GRT45
Transform & Win
 
GRT45's Avatar
 
Join Date: Jun 2010
Location: Texas
Posts: 2,914
Quote:
Originally Posted by Roger G23 View Post
Man. If I want to modify my G21SF to shoot .45 Super and .40 Super I hope the G21 slide can handle those pressures. You may know, .40 Super surpasses 10mm velocities and muzzle energy.
There is no need to worry about the structural integrity of the G21 slide with .45 Super or .40 Super affecting the safe operation. The added mass of the G20 slide was left there to slow the recoil reaction (unlocking) for the higher energy 10mm round and to attenuate felt recoil, but not as a structural requirement for safe operation. You must contend with a higher slide velocity with the G21 slide, of course, and mass is king, but that can be partially compensated for with a stronger recoil spring in the G21 slide to absorb some of the additional kinetic energy. Nevertheless, the felt recoil with the converted G21 will always be a bit more than a G20 with the same recoil spring and choice of ammo.

I've made the conversions with a G30 pistol with no ill effects. However, in the case of .40 Super and .460 Rowland it was necessary to include threaded barrels and a compensator in order to add mass and delay unlocking with the lighter slide. That will not be necessary for the G21 converted to shoot .45 Super or .40 Super.

You might enjoy watching the two excellent videos below produced by Ammo Test on YouTube if you haven't seen them already. Ammo Test is registered at Glock Talk with the user name icelandicstud.

Glock 21 45 Super Ammo Test - Accuracy, Velocity, Recoil

Glock 21 40 Super Ammo Test - Accuracy, Velocity, Recoil
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
: Strictly monogamous, I have one Glock and one woman.
GLOCK Certified Armorer,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Member,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Endowment Member, Eagle Scout

Last edited by GRT45; 08-21-2013 at 21:58..
GRT45 is offline   Reply With Quote
Old 08-21-2013, 22:36   #27
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by GRT45 View Post
There is no need to worry about the structural integrity of the G21 slide with .45 Super or .40 Super affecting the safe operation. The added mass of the G20 slide was left there to slow the recoil reaction (unlocking) for the higher energy 10mm round and to attenuate felt recoil, but not as a structural requirement for safe operation. You must contend with a higher slide velocity with the G21 slide, of course, and mass is king, but that can be partially compensated for with a stronger recoil spring in the G21 slide to absorb some of the additional kinetic energy. Nevertheless, the felt recoil with the converted G21 will always be a bit more than a G20 with the same recoil spring and choice of ammo.

I've made the conversions with a G30 pistol with no ill effects. However, in the case of .40 Super and .460 Rowland it was necessary to include threaded barrels and a compensator in order to add mass and delay unlocking with the lighter slide. That will not be necessary for the G21 converted to shoot .45 Super or .40 Super.

You might enjoy watching the two excellent videos below produced by Ammo Test on YouTube if you haven't seen them already. Ammo Test is registered at Glock Talk with the user name icelandicstud.

Glock 21 45 Super Ammo Test - Accuracy, Velocity, Recoil

Glock 21 40 Super Ammo Test - Accuracy, Velocity, Recoil
Really appreciate the info. and reassurance. I have just recently (two days ago) seen his videos. It's actually what sparked my interest in this. I subscribed to his channel and asked him some questions. He has been extremely generous and helpful in sharing his knowledge about the subject. A real stand up guy.
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC
Roger G23 is offline   Reply With Quote
Old 08-22-2013, 11:39   #28
Arnold Kuhl
Senior Member
 
Join Date: Apr 2013
Location: NE Tennessee
Posts: 1,111
GRT: Am interested in trying out the .45 Super, preferably 230gr., in my G21SF. I have a KKM 4.6" bbl, and have ordered a combo kit from Wolff. It's a 22 lb. recoil spring and stainless steel guide rod.

Is this suitable in YHO, or do you think I should go with an increased power spring (24 lb.) or a reduced power spring (20 lb.)? Also, do I need a shock buffer?

Thanks for your input. Never shot .45 Super before.

AK
Arnold Kuhl is offline   Reply With Quote
Old 08-22-2013, 12:19   #29
GRT45
Transform & Win
 
GRT45's Avatar
 
Join Date: Jun 2010
Location: Texas
Posts: 2,914
Quote:
Originally Posted by Arnold Kuhl View Post
GRT: Am interested in trying out the .45 Super, preferably 230gr., in my G21SF. I have a KKM 4.6" bbl, and have ordered a combo kit from Wolff. It's a 22 lb. recoil spring and stainless steel guide rod.

Is this suitable in YHO, or do you think I should go with an increased power spring (24 lb.) or a reduced power spring (20 lb.)? Also, do I need a shock buffer?

Thanks for your input. Never shot .45 Super before.

AK
The Wolff guide rod and 22 lb. recoil spring will be good with the G21SF and .45 Super. Wolff spring ratings are accurate and something in the 21-23 lb. range from Wolff works best for me with the Underwood 45 Super 230gr Speer Bonded JHP ammo. In comparison to Wolff, the strength of ISMI springs tend to measure less than their stated ratings in my experience. I'm running a Wolff 21 lb. dual recoil spring set in my Gen4 G30 for 45 Super now.

One can overdo recoil spring strength, so it shouldn't be assumed that the stronger the spring the better. Felt recoil will increase with a stronger recoil spring and one that is too strong will induce failure-to-feed malfunctions with weak loads in practice ammo. A Wolff 22 lb spring is a good compromise for the Gen3 G21.

I don't recommend a shock buffer for this application in a Glock. The G21 polymer frame can handle 45 Super no problem. I don't favor tinkering with the interior clearances by introducing a part that isn't durable or required.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
: Strictly monogamous, I have one Glock and one woman.
GLOCK Certified Armorer,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Member,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Endowment Member, Eagle Scout

Last edited by GRT45; 09-10-2013 at 17:40..
GRT45 is offline   Reply With Quote
Old 08-22-2013, 12:48   #30
Arnold Kuhl
Senior Member
 
Join Date: Apr 2013
Location: NE Tennessee
Posts: 1,111
The Wolff spring and rod should get here anytime now. Only problem is Underwood .45Super ammo is still out of stock, and I don't want to break the bank by paying more than a dollar per round someplace else.

Thanks for the feedback.
AK
Arnold Kuhl is offline   Reply With Quote
Old 08-22-2013, 16:16   #31
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by Arnold Kuhl View Post
The Wolff spring and rod should get here anytime now. Only problem is Underwood .45Super ammo is still out of stock, and I don't want to break the bank by paying more than a dollar per round someplace else.

Thanks for the feedback.
AK
I've got good news for you. Look what just came in.

http://www.midwayusa.com/product/974...cket-box-of-50
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC
Roger G23 is offline   Reply With Quote
Old 08-22-2013, 16:20   #32
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by GRT45 View Post
The Wolff guide rod and 22 lb. recoil spring will be good with the G21SF and .45 Super. Wolff spring ratings are accurate and something in the 21-23 lb. range from Wolff works best for me with the Underwood 45 Super 230gr Speer Bonded JHP ammo. In comparison to Wolff, the strength of ISMI springs tend to measure less than their stated ratings in my experience. I'm running a Wolff 21 lb. dual recoil spring set in my Gen4 G30 for 45 Super now.

One can overdo recoil spring strength, so it shouldn't be assumed that the stronger the spring the better. Felt recoil will increase with a stronger recoil spring and one that is too strong will induce failure-to-feed malfunctions with weak loads in practice ammo. A Wolff 22 lb spring is a good compromise for the G21.

I don't recommend a shock buffer for this application in a Glock. The G21 polymer frame can handle 45 Super no problem. I don't favor tinkering with the interior clearances by introducing a part that isn't durable or required.
Really value your points here. Two days ago I ordered a 24 lb. Wolff spring. I'll just exchange it for a 22 lb. once it arrives.
Question: Do the striker springs that come with the "combo pack" correlate to the specific weight also? Is using an extra power striker spring also very important?
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC
Roger G23 is offline   Reply With Quote
Old 08-22-2013, 16:28   #33
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by GRT45 View Post
The Wolff guide rod and 22 lb. recoil spring will be good with the G21SF and .45 Super. Wolff spring ratings are accurate and something in the 21-23 lb. range from Wolff works best for me with the Underwood 45 Super 230gr Speer Bonded JHP ammo. In comparison to Wolff, the strength of ISMI springs tend to measure less than their stated ratings in my experience. I'm running a Wolff 21 lb. dual recoil spring set in my Gen4 G30 for 45 Super now.

One can overdo recoil spring strength, so it shouldn't be assumed that the stronger the spring the better. Felt recoil will increase with a stronger recoil spring and one that is too strong will induce failure-to-feed malfunctions with weak loads in practice ammo. A Wolff 22 lb spring is a good compromise for the G21.

I don't recommend a shock buffer for this application in a Glock. The G21 polymer frame can handle 45 Super no problem. I don't favor tinkering with the interior clearances by introducing a part that isn't durable or required.
Although, I am going to modify (bought LWD 45-40S barrel) the G21SF to shoot .40 Super too.
Do you think the 22lb. spring will be OK for this "hotter" caliber? Or hold on to the 24lb. spring for .40 Super?
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC
Roger G23 is offline   Reply With Quote
Old 08-22-2013, 16:33   #34
GRT45
Transform & Win
 
GRT45's Avatar
 
Join Date: Jun 2010
Location: Texas
Posts: 2,914
Quote:
Originally Posted by Arnold Kuhl View Post
Only problem is Underwood .45Super ammo is still out of stock, and I don't want to break the bank by paying more than a dollar per round someplace else.
This Underwood XTP JHP offering, currently in stock, will do the job if the 230gr Speer Bonded JHP is out of stock. It's rated at 1100 fps and the price is 84/rnd. I may pick up a box or two myself.

45 Super 230 Grain XTP Jacketed Hollow Point Box of 50
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
: Strictly monogamous, I have one Glock and one woman.
GLOCK Certified Armorer,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Member,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Endowment Member, Eagle Scout

Last edited by GRT45; 08-22-2013 at 16:34..
GRT45 is offline   Reply With Quote
Old 08-22-2013, 16:55   #35
GRT45
Transform & Win
 
GRT45's Avatar
 
Join Date: Jun 2010
Location: Texas
Posts: 2,914
Quote:
Originally Posted by Roger G23 View Post
Although, I am going to modify (bought LWD 45-40S barrel) the G21SF to shoot .40 Super too.
Do you think the 22lb. spring will be OK for this "hotter" caliber? Or hold on to the 24lb. spring for .40 Super?
Hold on to your Wolff 24 lb. recoil spring when it comes in for the .40 Super conversion. I think you will appreciate having the 24 lb spring with the 40 Super barrel without a compensator. The 24 lb. RSA will work with .45 Super ammo although it may kick a bit harder, assuming you will be shooting full-power 45 Super ammo. You will probably find it necessary/desirable to reinstall the factory RSA when shooting low-power 45ACP practice ammo for plinking.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
: Strictly monogamous, I have one Glock and one woman.
GLOCK Certified Armorer,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Member,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Endowment Member, Eagle Scout

Last edited by GRT45; 08-22-2013 at 16:59..
GRT45 is offline   Reply With Quote
Old 08-22-2013, 17:06   #36
GRT45
Transform & Win
 
GRT45's Avatar
 
Join Date: Jun 2010
Location: Texas
Posts: 2,914
Quote:
Originally Posted by Roger G23 View Post
Question: Do the striker springs that come with the "combo pack" correlate to the specific weight also? Is using an extra power striker spring also very important?
Wolff includes a stock 5-lb. firing pin spring with their recoil springs. Just keep them for spare parts. Here is the statement from the Gunsprings.com website:
"Wolff recoil springs for use in Glock pistols are available with load-rated specifications to tailor the recoil function to individual needs. Due to the design of the Glock pistol, all Glock recoil springs now include a factory strength replacement striker spring."
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
: Strictly monogamous, I have one Glock and one woman.
GLOCK Certified Armorer,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Member,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Endowment Member, Eagle Scout

Last edited by GRT45; 08-22-2013 at 17:07..
GRT45 is offline   Reply With Quote
Old 08-22-2013, 17:07   #37
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by GRT45 View Post
Hold on to your Wolff 24 lb. recoil spring when it comes in for the .40 Super conversion. I think you will appreciate having the 24 lb spring with the 40 Super barrel without a compensator. The 24 lb. RSA will work with .45 Super ammo although it may kick a bit harder, assuming you will be shooting full-power 45 Super ammo. You will probably find it necessary/desirable to reinstall the factory RSA when shooting low-power 45ACP practice ammo for plinking.
I'll be shooting Underwood and Buffalo Bore in both calibers.
I got a LWD threaded barrel and LWD compensator for the .45 Super and a LWD 6'' 45-40S barrel.
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC

Last edited by Roger G23; 08-22-2013 at 17:07..
Roger G23 is offline   Reply With Quote
Old 08-22-2013, 17:09   #38
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by GRT45 View Post
Wolff includes a stock 5-lb. firing pin spring with their recoil springs. Just keep them for spare parts. Here is the statement from the Gunsprings.com website:
"Wolff recoil springs for use in Glock pistols are available with load-rated specifications to tailor the recoil function to individual needs. Due to the design of the Glock pistol, all Glock recoil springs now include a factory strength replacement striker spring."
Wow, OK. Just keep the stock striker spring in place.
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC

Last edited by Roger G23; 08-22-2013 at 17:14..
Roger G23 is offline   Reply With Quote
Old 08-22-2013, 17:17   #39
GRT45
Transform & Win
 
GRT45's Avatar
 
Join Date: Jun 2010
Location: Texas
Posts: 2,914
Quote:
Originally Posted by Roger G23 View Post
Wow, OK. That being said...do they even make "extra power" striker springs? Do I need to find and order them shooting these calibers?
Glock does make a 28 Newton (6.29 lbf - red) and 31 Newton (7 lbf - blue) firing pin spring for special purpose ammo with extremely hard primers. These extra-power springs are not necessary (or desirable) for the caliber conversions you have planned.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
: Strictly monogamous, I have one Glock and one woman.
GLOCK Certified Armorer,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Member,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
Endowment Member, Eagle Scout
GRT45 is offline   Reply With Quote
Old 08-22-2013, 17:20   #40
Roger G23
Glock Guy
 
Roger G23's Avatar
 
Join Date: Jun 2010
Location: The Gunshine State
Posts: 2,148
Quote:
Originally Posted by GRT45 View Post
Glock does make a 28 Newton (6.29 lbf - red) and 31 Newton (7 lbf - blue) firing pin spring for special purpose ammo with extremely hard primers. These extra-power springs are not necessary (or desirable) for the caliber conversions you have planned.
I see you shoot the G30. I heard factory mag springs feed .45 Super fine. Do you know if that's the case with the G21 also or do I need Wolff extra power mag springs?
__________________
G17 * G23 * G26 * G19 OD Green * M&P40c * M&P40 * M&P9 Shield (x2) * M&P40 Shield * M&P9 Pro Series * Kahr CM9 * CZ 75 SP-01 Shadow * CZ 75 P-07 Duty * FN FNS-40 * Canik 55 Stingray-C * SAR B6PC

Last edited by Roger G23; 08-22-2013 at 17:39..
Roger G23 is offline   Reply With Quote

 
  
Reply


Tags
10mm, conversion, glock 20, glock 21
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 02:24.




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


Users Currently Online: 686
139 Members
547 Guests

Most users ever online: 2,244
Nov 11, 2013 at 16:42