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 08-29-2010, 20:18   #76
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
Quote:
Originally Posted by hypnagogue View Post
Back of the envelope calculations seem to show that the "breech opens too fast" argument is null, at least with the G20 and G29 -- the slide weight is sufficient to keep it locked up until the bullet exits the barrel. Thus any explanation would have to be with slower powders burning slower due to the slide velocity reducing the pressure (unless someone else has an Idea They Would Like To Share). This effect is going to be powder-specific, with fast powders showing almost no effect, and slower powders showing the most.

So, your test with Blue Dot sounds like a good idea, since that is a slow powder. Testing with a G29 is not quite ideal, as the shorter barrel isn't going to get the most from slower powders anyway, but it might show some effect. Unfortunately, your Blue Dot test won't have any relevance with respect to Double Tap ammo, unless we happen to know that Blue Dot is the powder that Mike uses (I think not...).
Some notes:

First of all, I am using an extended barrel in my G29. It is 4.45" in length. That puts my particular G29 very close to a G20 in barrel length. Certainly, 0.15" is not going to make a significant difference in velocities based on burn rates.

I do not believe that McNett uses blue dot for his commercial loads. I would expect he uses a commercially available powder that hobbyist hand loaders cannot get their hands on in small quantities without working with commercial loaders who might have stumbled on to what he has been using. I expect that his powder is going to be closer to AA#9 in burn speed, but that is simply speculation since I really don't know what he is using.

I just know it's not producing velocities that meet the claims on his boxes.

Unfortunately, since I put a bullet through the top of my chrony case today (table was too high for margin of error - will not make that mistake twice!), knocking into some internal parts - I will not be able to test any more until I either repair or replace the chrono (hoping the dealer has some parts available).

The idea of spring tension vs. velocity is worth testing anyway.

I am going to order a 24# spring and get the chrono replaced or repaired as soon as I am able so I can post my own findings.

I could also easily test the theory of 800x, which is slower than Blue dot. Before ripping a nice long hole through the case I was able to get through enough strings to know how to match the velocity of double tap's 200 gr. "controlled expansion" rounds (based on my small sample of 3 measured yesterday), so I suppose we could emulate the spring vs. velocity using that load...
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21
Kegs is offline   Reply With Quote
Old 08-29-2010, 20:28   #77
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
One more note:

I am using a 21# spring, not a 22#. I somehow got mixed up about that. Not sure how. The 21# springs aren't strong enough for any of the loads I run through this gun.
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21
Kegs is offline   Reply With Quote
Old 08-31-2010, 08:12   #78
MalumProhibitum
Senior Member
 
MalumProhibitum's Avatar
 
Join Date: Jul 2006
Location: Georgia
Posts: 540
Quote:
Originally Posted by alpha6164 View Post
UPDATE:


Someone recommended that changing the spring to a heavier will improve my chrono. I ordered the Wolff 24lb spring and guide rod combination.

I took the G20 to the range yesterday and shot the same ammo with the new spring. The conditions were pretty identical, both days in the low 90s temp wise and same humidity. These tests are a week apart so it is right on. Five shot string and posting the average.



Last week with stock barrel and spring: These are average

DT 135gr = 1463 ft/sec
DT 200gr XTP= 1089 ft/sec
DT 180 XTP = 1211 ft/sec


Yesterday with stock barrel and 24lb spring and guide rod: These are average

DT 135gr = 1582 ft/sec
DT 200gr XTP= 1214 ft/sec
DT 180 XTP = 1242 ft/sec


There is no question that 24lb spring helped. What is amazing is that it helped the most with the lightest bullet and in ascending order the heavier the bullet the less it improved with the heavier spring but all improved. I guess that there is so much more pressure/powder in the 135gr load that opens the breach face faster and longer changing the velocity.

Just wanted to post this because it somewhat gets DT off the hook. It is possible that at elevation (i am at seal level) those numbers can be another 50ft/sec faster which would be closer to their advertised data.
Just copying to this page, so we do not lose track of what we were originally testing, doubting, or confirming.
__________________
I don't mean to be condescending (which means to talk down to) . . .

Last edited by MalumProhibitum; 08-31-2010 at 08:12..
MalumProhibitum is offline   Reply With Quote
Old 08-31-2010, 18:04   #79
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
Quote:
Just copying to this page, so we do not lose track of what we were originally testing, doubting, or confirming.
Good idea. I sent the chrono in yesterday for repair and should have it back within a couple weeks or so. I ordered the 23# springs today from Wolff. I believe it is the max spring they had for the G29. Should work much better for my average load (nuke).

I still have a few rounds of that sissified double tap left, and I have my stock spring and stock barrel, which is obviously easy enough to change back. I will remain skeptical unless proven otherwise through my own results.

Stay tuned.
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21

Last edited by Kegs; 08-31-2010 at 18:06..
Kegs is offline   Reply With Quote
Old 08-31-2010, 18:12   #80
cowboywannabe
you savvy?
 
cowboywannabe's Avatar
 
Join Date: Jan 2001
Location: on a planet near you
Posts: 20,547
it seems Buffalo Bore is the only commercially recognized regular player for real 10mm loads. theyre the only ones that meet their box flap claims, or at least very close to it no matter who is shooting it and no matter if they have a stoch Glock or after market springs.....still wish they made a 165grainer~ that i could afford.

im leary of the 180grainer at 1350fps for personal defense against bad guys.....seems it would pass through the average bad guy with ease. maybe if this load were toned down to what the others claim to be....
__________________
with Sarah Jane, Leela, Romana, Nyssa, and Tegan.

Facts are no match against enthusiasm and ignorance...

Last edited by cowboywannabe; 08-31-2010 at 18:12..
cowboywannabe is offline   Reply With Quote
Old 08-31-2010, 19:24   #81
Berto
woo woo
 
Berto's Avatar
 
Join Date: Sep 2003
Location: WA
Posts: 28,684


Tim at BB actually mentions going to a heavier spring in the G20 to help reduce velocity extremes you will get with the stock ones.
__________________
...Then I found a place it's dark and it's rotted
it's a cool, sweet kinda-place where the copters won't spot it.
-T Hip
Berto is offline   Reply With Quote
Old 09-01-2010, 08:45   #82
PBRLite
Senior Member
 
Join Date: Jan 2009
Location: Kansas
Posts: 611
Not sure if this has been covered or asked, and maybe it wouldn't make a lick of difference, but would shooting the gun in a machine rest like a "Ranson Rest" make any difference in velocity readings?

Along with a stronger recoil spring, and firing the gun 15 feet back from your chrono?

Last edited by PBRLite; 09-03-2010 at 05:20..
PBRLite is offline   Reply With Quote
Old 09-02-2010, 06:22   #83
morphoffroad
Junior Member
 
Join Date: Jul 2008
Posts: 3
High Power Loads - Stronger Recoil Spring

One cause of lower measured velocity than DT's published velocity for full power loads may be that the G20 breach is unlocking prematurely. I had similar low results until I installed a stronger recoil spring.
morphoffroad is offline   Reply With Quote
Old 09-02-2010, 20:18   #84
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
Quote:
Originally Posted by morphoffroad View Post
One cause of lower measured velocity than DT's published velocity for full power loads may be that the G20 breach is unlocking prematurely. I had similar low results until I installed a stronger recoil spring.
How much stronger is the spring you installed?
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21
Kegs is offline   Reply With Quote
Old 09-02-2010, 20:22   #85
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
Quote:
Originally Posted by cowboywannabe View Post
im leary of the 180grainer at 1350fps for personal defense against bad guys.....seems it would pass through the average bad guy with ease. maybe if this load were toned down to what the others claim to be....
The main things I would be concerned about at a gun fight is #1 NOT GETTING SHOT, and #2 SHOOTING THE OTHER GUY BEFORE HE SHOOTS ME.

Get your priorities straight - and bring enough gun!
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21
Kegs is offline   Reply With Quote
Old 09-08-2010, 01:01   #86
Mike5560
Senior Member
 
Join Date: Mar 2005
Posts: 313
Quote:
Originally Posted by cowboywannabe View Post
and i thought that was common knowledge....the 17# spring being stock for the 10mm just like it is for the 9mm in the G17....spare me the heavier slide stuff folks....thats comparing ounces of slide weight to pounds of force of the stock vs. after-market springs...

its my feeling that Glock decided that the 17 pound spring along with the heavier slide of the G20 was plenty for the run of the mill watered down stuff that Rem. Fed. Win. Hornanday...etc puts out, and theyre right. but this combos is far from optimal for true 10mm powered loads.
I thought this was common knowledge as well. I basically impulse bought my G20 since I have .40/10mm dies and after about 5 minutes of online research. During that time, I found a page about the G20 and the reviewer noted extreme velocity spreads with the factory spring. Velocities were increased and more consistent with a heavier one. This has been talked about on the forum here as well.
__________________
"Only the dead have seen the end of war" -Plato
Mike5560 is offline   Reply With Quote
Old 09-08-2010, 16:39   #87
gatorboy
Senior Member
 
Join Date: Jul 2001
Posts: 2,918
Quote:
Originally Posted by Kegs View Post
One more note:

I am using a 21# spring, not a 22#. I somehow got mixed up about that. Not sure how. The 21# springs aren't strong enough for any of the loads I run through this gun.
The Wolff springs for the 29/30 are mostly odd numbered, mostly even for all other models with some exceptions.
gatorboy is offline   Reply With Quote
Old 09-10-2010, 22:12   #88
sgtbones
Senior Member
 
Join Date: Mar 2010
Posts: 247
A close friend of mine just shot 180gr (real Gold Dots) Swamp Fox AMMO
through a chronogaph. AVERAGE FPS WAS 1380 !!!!!!!!
sgtbones is offline   Reply With Quote
Old 09-11-2010, 03:19   #89
Sheepdog Scout
Behind you!
 
Sheepdog Scout's Avatar
 
Join Date: Jan 2010
Location: Who knows?
Posts: 3,533
Quote:
Originally Posted by sgtbones View Post
A close friend of mine just shot 180gr (real Gold Dots) Swamp Fox AMMO
through a chronogaph. AVERAGE FPS WAS 1380 !!!!!!!!
Nice! I've got some SwampFox ammo coming my way. I'm excited to try them.
__________________
http://www.aspca.org/donate
Sheepdog Scout is offline   Reply With Quote
Old 09-12-2010, 21:49   #90
Billy10mm
Senior Member
 
Join Date: Jun 2008
Location: Hartsdale, NY
Posts: 1,171
I ordered a box of the 200gr XTP from Mike .... got a box with the 200gr label, but the bullets were 180gr GD's.

Mike won't be seeing any more of my money until I start reading "DT has turned themselves around" reviews.
__________________
Billy
Glock 23
Fusion Tact-5 in 10mm
H&K P30S 9mm
Ruger SR22
Billy10mm is offline   Reply With Quote
Old 09-28-2010, 12:02   #91
MalumProhibitum
Senior Member
 
MalumProhibitum's Avatar
 
Join Date: Jul 2006
Location: Georgia
Posts: 540
Quote:
Originally Posted by Kegs View Post
Good idea. I sent the chrono in yesterday for repair and should have it back within a couple weeks or so. I ordered the 23# springs today from Wolff. I believe it is the max spring they had for the G29. Should work much better for my average load (nuke).

I still have a few rounds of that sissified double tap left, and I have my stock spring and stock barrel, which is obviously easy enough to change back. I will remain skeptical unless proven otherwise through my own results.

Stay tuned.
Ok, I am staying tuned.
__________________
I don't mean to be condescending (which means to talk down to) . . .
MalumProhibitum is offline   Reply With Quote
Old 10-06-2010, 17:19   #92
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
My conclusion is heavier recoil springs don't do SQUAT for increasing velocity.

Here's the skinny:


http://glocktalk.com/forums/showthre...6#post16101316
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21

Last edited by Kegs; 10-06-2010 at 19:32..
Kegs is offline   Reply With Quote
Old 10-06-2010, 18:32   #93
sgtbones
Senior Member
 
Join Date: Mar 2010
Posts: 247
Swamp Fox Ammo boys!!!!!!!!!!
sgtbones is offline   Reply With Quote
Old 10-06-2010, 19:16   #94
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
Quote:
Originally Posted by sgtbones View Post
Swamp Fox Ammo boys!!!!!!!!!!
Just saw his video. I edited this to say his ammo goes just about the same speed my 9.4gr. 800x load does. I have no idea how he can fire that in a stock Glock barrel without a great big smiley face on the case afterward.

I don't think I would attempt to fire that out of my stock G29.

1240 w/XTP out of a G20 stock barrel is going to be just about at the limits of the 37.k psi...

Finally...someone loading full power ammo!

One thing I would be a tad concerned about is how he can run one bullet through the chrono going 1250 and the next going 1200...That is a bit of a wide gap there.

Watch:

http://www.youtube.com/watch?v=sO9h-y0-p30
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21

Last edited by Kegs; 10-06-2010 at 19:36..
Kegs is offline   Reply With Quote
Old 10-07-2010, 03:10   #95
Sheepdog Scout
Behind you!
 
Sheepdog Scout's Avatar
 
Join Date: Jan 2010
Location: Who knows?
Posts: 3,533
I figure it's probably like he said. He was having issues with his chrono. They don't always work correctly.
__________________
http://www.aspca.org/donate
Sheepdog Scout is offline   Reply With Quote
Old 10-09-2010, 09:57   #96
DanaT
Pharaoh
 
DanaT's Avatar
 
Join Date: Feb 2005
Location: CO & Baden –Württemberg
Posts: 15,827
Blog Entries: 1
Here is what I have measure out of a stock G20 with 165gr Golden Saber Double Tap loads.

This testing was done at 8500ft altitude.

Note that I had a stock recoil spring in the pistol when the data was taken so some of the deviation is likely due to spring.


All numbers in Ft/sec
1395 1385 1420 1368 1349
1362 1381 1382 1358

Mean. 1378ft/sec
Std Dev. 21.57
% RSD. 1.57%

I am not sure if those load were claimed at 1400ft/sec of 1425ft/sec.

I also take measurements at about 15ft to avoid muzzle blast interferences.

All in all, given the accuracy of my measuring equipment (Shooting Chrony) I would say the number are in the ballpark.

If someone in this forum actually has a chrono calibrated to a NIST standard, then maybe they can make the statement that thier numbers are more accurate. But lets be honest. The chronos people are using are cheap off the shelf units (even an Oehler is cheap off the shelf and is the best commercially available).

To get more accuracy, you need to purchase much more expensive equipment. For example, how many of you have calibrated masses to check your reloading scales against? How many of you use a balances (scale) that has precision to +/- 0.1mg (0.0015grains) and accuracy to +/- 0.2mg (0.003grains)? This is the difference between a consumer reloading scale ($100) and a lab grade scale ($5000). Yet I bet all the blow hards would say that some powder measurements I took with a NIST calibrated scale as described above were wrong because their $100 untraceable scales said something different.

Take the knowledge here with grain of salt.

-Dana
__________________
Quote:
Twice a week? 14 times a month?
Quote:
2x4=8, not 14.
Many of the truths that we cling to depend on our point of view.
DanaT is offline   Reply With Quote
Old 10-10-2010, 09:06   #97
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
Good points, Dana! Standards of tolerance aside, your measurements seem to support my suggestion that DT's numbers are pretty close leaning toward a tad optimistic.
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21
Kegs is offline   Reply With Quote
Old 10-10-2010, 09:07   #98
OldCurlyWolf
Senior Member
 
OldCurlyWolf's Avatar
 
Join Date: Aug 2010
Posts: 732
Has anyone verified whether or not DT is using a pressure barrel for its velocity testing? A pressure barrel will consistently give higher velocities than a standard barrel.

__________________
I won't be wronged, I won't be insulted, and I won't be laid a hand on. I don't do those things to other people and I require the same of them.

Politicians should serve two terms, one in office and one in prison.(borrowed from RioKid)
OldCurlyWolf is offline   Reply With Quote
Old 10-10-2010, 09:19   #99
Kegs
Ol 8 fingers ;)
 
Kegs's Avatar
 
Join Date: Oct 2009
Location: Cold side of conus
Posts: 2,682
Quote:
Originally Posted by OldCurlyWolf View Post
Has anyone verified whether or not DT is using a pressure barrel for its velocity testing? A pressure barrel will consistently give higher velocities than a standard barrel.

As far as I can tell he uses actual Glock pistols for velocity and related testing. For pressure testing, he has other equipment.


http://glocktalk.com/forums/showthread.php?t=336612
__________________
"What's the down side to 10mm again? Oh, that's right, there isn't one."" Carrier21

Last edited by Kegs; 10-10-2010 at 09:22..
Kegs is offline   Reply With Quote
Old 02-27-2012, 19:10   #100
vaquero aleman
US ARMY 63D20H8
 
vaquero aleman's Avatar
 
Join Date: Jan 2009
Location: On the other side of the tracks
Posts: 687
Quote:
Originally Posted by cowboywannabe View Post
there are plenty of neophytes to bite on the 10mm loading and DT hype. they will take your place and you wont be missed....sadly.
Well, this "neophyte" switched from a G20 to a 21 and I geared up my rig for 45 Super so I guess now I will join the ranks of quiting DT, especially since they don't load 45 Super anyhoo.
__________________
G2930SF(.460 Rowland), The 21 Club #7663, The 10 Ring #7663.

http://www.glocktalk.com/forums/show....php?t=1474601
___________________________________________
Amateur Glock Modification Expert...
vaquero aleman is offline   Reply With Quote
Reply

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 04:27.



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


Users Currently Online: 668
196 Members
472 Guests

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