DoubleTap Ammo Velocities?

[9mmParabellum]

Does anyone here? Or can you point me in the right direction. I would like to know if the advertised velocities for Doubletap Ammo are true.

Another question. If the bullet velocity from the manufacturer is 1200fps and you load it to 1289fps would this mess with the bullets performance?

Better or worst.

[slugman]

I crono'ed many of Doubletaps 10mm a few years back and found that they are exagerated...some drastically. I found that the lighter the bullet weight they were closer (but still not close) to advertised velocitys. The 200+ grain bullets were about 150fps under advertised velocitys in a glock20:wow:

[Big Sam]

Well let's see. It actually depends on the load.

9mm in a Glock 17 the 124gr +P and 147gr +P were very close. Impressive.

357 mag in a 4" GP-100. 200 fps under quoted velocity.

45acp in Glock 21 and 30. With 230gr Gold Dot bullets, over 100 fps below 5" velocity but otherwise very impressive load.

Mostly Double Tap is pretty good ammo.

[Mountain10mm]

I second slugman. I've only tested the 200gr. XTP (when it was an XTP bullet) and the actual velocity was about 150fps slower than advertised. I think DT states 1250fps on the box and I averaged almost exactly 1100fps. That's still a relatively powerfull round though, but again, not as advertised.

[cowboywannabe]

they are very optomistic with their velocity claims, however they are still the fastest with regards to the wide variety of loads they offer. BB's 10mm is in real life what DT's 10mm claims but BB only makes a heavy load in this cartridge.

[glock20c10mm]

...would this mess with the bullets performance?
Generally no. In any case, it depends on many factors which include but are not limited to: the specific bullet in question, what you need the bullet to accomplish for your specific risk assessments if there are any, and on top of that, also, how much more speed we're talking about.

[RottnJP]

Really depends on the bullet. Gold Dot, for example, or XTP, seem to hold up pretty well from the data I've seen. Tough bullets. Golden Sabre, not so much- petals open too much, and it tends to separate the jacket. Hard cast or JSP designs aren't going to be bothered one bit by extra velocity.

[Pappy John]

The DT ammo I've chroned in the past has varied from higher to lower and right on the money.

Their 147 gr 9mm was right where they advertised at 1135.

10mm 165 gr was actually a bit high, at 1440 fps. Made me buy a KKM barrel for my G20 to stop the cases from ballooning.

The 10mm 200 gr was, as found by the posters above, much slower than advertised.

I'm disappointed that they dropped the GoldDot bullets from their line, but I guess the Golden Sabers are okay.

[BOGE]

...I'm disappointed that they dropped the GoldDot bullets from their line, but I guess the Golden Sabers are okay.

They had no choice: they couldn't get any as Speer was running 24/7 supplying the Great Ammo Frenzy after Obama's election. There may be other reasons as well, but this WAS the primary reason.

[TimP]

As someone who has never shot DT ammo, keep in mind that chronographs lie.... all of them. As a long range shooter, I use 3 different chronos and average the three out. Again, if DT is testing the ammo in tight chambers, it will also get more velocity.

Its the same way as dyno's for measuring horsepower. I witnessed my own Camaro pull 314whp on one dyno, then the next week it pulled 331 on one across town.

[Berto]

In the auto rounds, spring weight can also be a factor, esp with the 10mm and wide vel spreads.

[BOGE]

As someone who has never shot DT ammo, keep in mind that chronographs lie.... all of them...

Good point. DT is in Utah as well & altitude affects chrono readings also.

[glock20c10mm]

....chronographs lie.... all of them. As a long range shooter, I use 3 different chronos and average the three out.
How do you know they all lie? I mean sure, certainly there are plenty of things that will affect their readings, but how do you know one of the three you use isn't more accurate than than the other two? Not being a smart***, just asking, as I've yet to own a chronograph. What are the three models you currently own/use?

[TimP]

How do you know they all lie? I mean sure, certainly there are plenty of things that will affect their readings, but how do you know one of the three you use isn't more accurate than than the other two? Not being a smart***, just asking, as I've yet to own a chronograph. What are the three models you currently own/use?

no offense taken.

I use an Oehler 35P, and 2 different Pact models ( Professional XP Chronograph ,and a model 1 XP ). All of which are good chrono's, but i can take 3 IDENTICAL loads, put them in my rifle, and shoot those rounds through the chronos back to back to back in a span of 20 seconds, and get 3 different answers.

Meaning when I shoot my 280AI with 140gr noslers I may get this reading
Oehler : 3274fps
Pact pro : 3265fps
pact model 1 : 3210

obviously i made those numbers up, but that is usually the case, where 1 chrono will give a strange number and the other 2 are accurate.

The only real way to test this is to set up a target at 600 yards, and track your dope at 600 from your 100 yard zero. You can then plug in the drop of the bullet and the BC of the bullet and reverse calculate the FPS that physics said it had to be traveling at.

I hope that helped explain it.
Merry Christmas
Tim

[NonPCnraRN]

It is like the old proverb: "A man with one watch knows what time it is. A man with two watches is never certain what time it is." Tim, in your case is it always the same chrono that doesn't agree with the other two? I wouldn't expect the chronos to all have the exact same number but they should be close. Do you have experience where none of them have the same approximate results? Do you wait for the barreled action to cool between shots? Have you found that velocities increase as the gun heats up? Sorry for all the questions but anyone who uses 3 chronos must be meticulous in their testing technique and because of this your input is invaluable.

[TimP]

@nonPCnraRN

It typically is the Oehler that is different than the two Pacts, but after reverse calculations, it is always the closest to the calculated velocity. I believe this is because the Oehler uses 3 screens and the Pacts only use 2 screens. The Oehler will calculate, and average the velocity over the 2 segments, and the pacts only have 1 segment to compare.

Both of the pacts are typically within 1-2% of each other, and the oehler reads slightly faster than the the pacts. After reverse calculations, the Oehler is probably 80% of the time closer to the calculated velocity than the pacts.

In one test with a 260rem, the oehler was over 40fps SLOW on the calculated results, and the pacts were about 50fps slow. I was shooting these at 800 yards, and i wasnt needing as many mils to get to the targets and i thought I should.

Then when I tested a 6.5 grendel all three were within 10fps of the calculated velocity.

I will typically try to keep the barrel temp the same throughout the testing. Usually firing 2-3 shot to warm up the bore, then proceed with the test.

Yes velocity can increase as the gun heats up. When the chamber gets hotter it can cause case pressure to increase thus making the bullet faster.

I hope that helped and answered your question.

So in closing, Chronographs are an amazing tool to get a fairly accurate baseline data from, but its just one of the tools that works.

All the best
Tim

[Big Sam]

I have shot half a dozen different buffalo bore loads over my chrono. All have been very close to their published velocities. It also helps that they publish velocities for different guns and barrel lengths. I recently fired their 45 acp 230gr +P stuff. Whoa! but that was some strong stuff at an honest 940 fps out of a Glock 21.

I don't know why the Double Tap stuff claimed velocities go from reality to fantasy and back again so easily. But if you don't get tied up in that and accept their standard pressure, for example, 230gr Gold Dot does 890 fps out of my Glock 21, then you'll probably be a happy camper. It's not close to their claim but it is a great standard pressure load. Sadly not made anymore but the new Golden Saber may be as good. In 9mm I have migrated over to the Buffalo Bore 147gr +P+ (honest 1180fps out of a G17 and 1120 fps out of a G26) but have stayed with the Double Tap 230gr Gold Dot loads at least until my supply runs out.

[cowboywannabe]

Big Sam, its not the fact that the velocities are still descent. its the fact that folks pay for 135gr. @ 1600fps in 10mm and dont get near that when using the same kind of gun used to est. velocity claims.

[glock20c10mm]

no offense taken.

I use an Oehler 35P, and 2 different Pact models ( Professional XP Chronograph ,and a model 1 XP ). All of which are good chrono's, but i can take 3 IDENTICAL loads, put them in my rifle, and shoot those rounds through the chronos back to back to back in a span of 20 seconds, and get 3 different answers.

Meaning when I shoot my 280AI with 140gr noslers I may get this reading
Oehler : 3274fps
Pact pro : 3265fps
pact model 1 : 3210

obviously i made those numbers up, but that is usually the case, where 1 chrono will give a strange number and the other 2 are accurate.

The only real way to test this is to set up a target at 600 yards, and track your dope at 600 from your 100 yard zero. You can then plug in the drop of the bullet and the BC of the bullet and reverse calculate the FPS that physics said it had to be traveling at.

I hope that helped explain it.
Merry Christmas
Tim
Thanks for being open and honest about it.

By chance have you ever lined up up all three chronos end to end and fired through all 3 with a single shot? I would think that would be the way to really test them, and then swapping their positions for another shot...

Thoughts?


Merry Christmas,
Craig

[glock20c10mm]

Big Sam, its not the fact that the velocities are still descent. its the fact that folks pay for 135gr. @ 1600fps in 10mm and dont get near that when using the same kind of gun used to est. velocity claims.
:agree: I just saw some chrono results for the DT 135gr Nosler bullet load on YouTube a day or two ago, 5 consecutive shots, and the results were:

High Velocity - 1484 fps
Low Velocity - 1285 fps

And yes, those #s are correct in so much as I didn't mistype them and saw the readings on the guy's chrono as he shot them.

Makes me feel like :impatient: and a little :fist:.

Of interesting note, the guy also tested the Reed's Ammo 135gr Nosler bullet load, rated for 1500fps, and the results were:

High Velocity -1507 fps
Low Velocity - 1379 fps

When I add all this up, it raises some questions!
1) Why aren't the DT loads getting at least a bit better velocity than they are?
2) After seeing results of 2 different manufacturers for the same bullet launched from the same cartridge, is it not possible to get AT LEAST A LOT MORE CONSISTENCY THAN THAT?!?!?

I mean what the #@$& ???!!!??? :headscratch:


I have now decided 100% out my coming up tax return money I will own a CED M2 Chornograph with the optional "True" IR lighting option!!! Even without IR lighting, this chrono has sensors that automatically optimize for the available light.

I would expect this chrono is the most accurate available without going to complete commercial equipment. And if anyone is thinking about any other brand chrono with a supposedly IR lighting option, be sure to NOT be fooled by colored light filters, sensors with two LED's that reflect off the underside of the tops or refrigerator light bulbs in tin boxes.

An independant lab tested the CED M2 against others and found: All calibers measured by the CED were within 0.2% (99.8%) of lab recordings, from 0.327% for 223 Rem to 0.081 for 45ACP. Results were better than all other chronographs. (The venerated Oehler tested 0.3% behind the CED.) The new IR emitters will virtually eliminate any variation caused by differences in natural lighting. If you need a chronograph that will approach the accuracy of commercial radar lab equipment, but do not want to spend $ BIG BUCKS $, try a CED chronograph.

I'm sold on it.

Obviously me getting a chronograph in the relatively near future doesn't change the seriously BS manufacturer claims by DT with their 10mm 135gr Nosler bullet load, but I'll be curious to test it myself and post my findings as well.



Good Shooting,
Craig

[WiskyT]

The only real way to test this is to set up a target at 600 yards, and track your dope at 600 from your 100 yard zero. You can then plug in the drop of the bullet and the BC of the bullet and reverse calculate the FPS that physics said it had to be traveling at.

I hope that helped explain it.
Merry Christmas
Tim

The BC on your bullets is off, not your chronos. BC's are rarely, if ever right. Add to that the fact that a light tail wind could raise your point of impact a lot, and it doesn't even have to be on the firing line. We only have a 300 yard range, and the wind is different throughout the whole flight of the bullet. Unless you are shooting in a vacuum tube, or you know for a fact that the BC is correct AND the exact wind conditions encountered by the bullet on it's trip, you'd do better to trust your chrono and not your slide rule.

[BOGE]

So, why don't the people who have had what they term bad results with DT ammo simply reload their own ammo to their own specs? :dunno:

[glock20c10mm]

The BC on your bullets is off, not your chronos. BC's are rarely, if ever right. Add to that the fact that a light tail wind could raise your point of impact a lot, and it doesn't even have to be on the firing line. We only have a 300 yard range, and the wind is different throughout the whole flight of the bullet. Unless you are shooting in a vacuum tube, or you know for a fact that the BC is correct AND the exact wind conditions encountered by the bullet on it's trip, you'd do better to trust your chrono and not your slide rule.
Speaking of BS ballistic coeficients being exaggerated, from what I understand, that is even more so the case with all the relatively new fangled .204 caliber bullets out there. Supposedly those in the know have switched back from .204s to .224s of one variation or another for just such reason.

[glock20c10mm]

So, why don't the people who have had what they term bad results with DT ammo simply reload their own ammo to their own specs? :dunno:
I don't know. Why?

[BOGE]

I don't know. Why?

I know why!! So they can have more time to piss & moan on GT while eating Twinkies instead of reloading! :rofl:

[PghJim]

Tim explains on BB, that for Glocks, the recoil spring is a big factor for less variation between rounds and 150fps is normal with some springs. As far as DT, I have seen some right on and some 100+ fps low. The last one I bought was the 125gr Seirra 357 sig JHP, which Mike says will go 1,500fps from a 4.5" barrel. That is exactly what I am averaging from my Glock with a 4.5" barrel. The same length of barrel between two gun, or just two different barrels can have 100+ fps variation. On my G23 I get 1305 FPS from the stock barrel and 1,375 FPS from my KKM barrel with Corbon 40 S&W 135gr loads. I do not think Mike is purposefully inflating the velocity numbers, but rather are true variations between my setup and weather conditions and his.

[TimP]

The BC on your bullets is off, not your chronos. BC's are rarely, if ever right. Add to that the fact that a light tail wind could raise your point of impact a lot, and it doesn't even have to be on the firing line. We only have a 300 yard range, and the wind is different throughout the whole flight of the bullet. Unless you are shooting in a vacuum tube, or you know for a fact that the BC is correct AND the exact wind conditions encountered by the bullet on it's trip, you'd do better to trust your chrono and not your slide rule.

I'm not saying that my way is an absolute truth, but it works for me and the games I play. Besides, even a 20mph tail wind is only adding 29.2fps to the velocity

[WiskyT]

I'm not saying that my way is an absolute truth, but it works for me and the games I play. Besides, even a 20mph tail wind is only adding 29.2fps to the velocity



In one test with a 260rem, the oehler was over 40fps SLOW on the calculated results, and the pacts were about 50fps slow. I was shooting these at 800 yards, and i wasnt needing as many mils to get to the targets and i thought I should.

All the best
Tim

So, 29fps doesn't matter, but 40fps does?

[Kegs]

So, why don't the people who have had what they term bad results with DT ammo simply reload their own ammo to their own specs? :dunno:


This isn't the first time this topic has been the discussion on the 10 ring.

I know that chronos aren't necessarily accurate and there are reasonable explanations for that. I know mine has been calibrated within the year, but I am pretty sure it was not calibrated at this elevation and at the exact relative air pressure, etc.

What I found with the Double tap 200gr. "controlled expansion" load is that it was somewhat optimistic. It suggests 1250 fps w/ 4.6" bbl., what I got was 1180 avg. out of a 4.45" barrel. The barrel I am testing has a different chamber and different rifling pattern than stock, but I would not expect more than 20 fps difference based on those numbers.

Personally, I have no reason to believe that my chornograph is consistently wrong to the point that whenever I have tested double tap ammo, it's always lower than advertised.

That is especially the case when I used loads others have used in their G20s and the velocity is virtually the same as they posted.

.22lr shot out of my AA kit is also a point of reference.

Controls are what these are called in science - and although there are many variables, my conclusions are this:

1. Recoil springs don't make a significant difference in velocity.
2. Elevation/air pressure/temperature WILL make a significant difference in velocity.
3. Light errors WILL make a significant difference in velocity
4. Double tap ammo ratings are somewhat optimistic for most of lower than 5800' elevation America.

As for loading my own, I do and it is fairly easy to outpace double tap ammo without going over (assumption based on interpolation and extrapolation of known figures) SAAMI pressure (although "book loads" will not get you there.

I would like to test Swamp fox ammo, as I have a notion that if I run that through my chrono, it's going to be what was advertised (if any figure other than "maximum velocity" is on the box) - or at least the results will be similar to what has been posted on youtube.

:wavey:

[BOGE]

...I would like to test Swamp fox ammo, as I have a notion that if I run that through my chrono, it's going to be what was advertised (if any figure other than "maximum velocity" is on the box) - or at least the results will be similar to what has been posted on youtube.

:wavey:

Interesting link, however whoever set up the website needs to be fired. Clicking on 9mm brings up .380 Auto Youtube videos. :upeyes: :whistling:

http://www.swampfoxammo.com/

[Mwinter]

FWIW the DT loads I've chronographed have been very close to advertised/sticker specs.

The first was a custom load I had McNett cook up for me. The JHP and the matched practice load were typically within 15-20 fps of the advertised velocity (DFW TX area, various temps).

The second was the 115gr GDHP 9x25D....advertised at 1800fps; single chrony shot at an ATK gel lab was 1801fps.

All these were at least 3 years ago or more, FYI.

The spec sheets on many Speer LE pistol-cal products are +/- 50fps, so anything resembling consistency is a big plus in my book. I wish like hell ProLoad was still turning out their own stuff....best I've ever chronied in 9mm and .45ACP.

[unit1069]

The second was the 115gr GDHP 9x25D....advertised at 1800fps; single chrony shot at an ATK gel lab was 1801fps.

That 9X25 screamer must be an experience!

Is it as loud as .357sig?

[TimP]

So, 29fps doesn't matter, but 40fps does?

oh it matters, I was just pointing out that it takes more than just a little wind to adversely affect a bullets speed. Though even at 20mph, you would have to be directly parallel to the wind to even get the full value anyway.

All the best
Tim

[Mwinter]

The DT 9x25D loads, esp the 115, 95 and 90gr loads, are especially loud indoors. Moreso than a .357SIG factory load, at least in my estimation.

The lightest DT 9x25D FMJ loads (95?) have been advertised at close to 2000fps, and based on their terminal performance on certain V50 barriers I'd say that's close if not on the dot.

FYI the 9x25D loads I have only shot through a 6" stainless BarSto, and the 10mm loads were from a stock G20.

The 9x25D is a helluva 'testbed' in the service handgun envelope, and I for one was SO glad to see DT make loads for it. I do not normally enjoy reloading, esp. for semiauto bottleneck cartridges.