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Taccom ULW 9 mm barrel.....


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Is anyone having problems with a shorter throat in their Taccom ULW upper? My 100gr loads stick in the leade every time, but the same loads run fine in two of my friends' ULW uppers. I'm about to ream mine but thought I'd see what everyone else has experienced before I go through the extra effort.


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The longer throat on the Taccom barrel is one of its selling points.  If you have one that is short, it might be good to contact Tim.  If there is a problem I'm sure he would like to know about it.

 

P.S.  I'm still trying to find a good long range (100 to 200 yards) 9mm load for the barrel you throated for me. The barrel feeds everything 100% so that part was a huge success.

 

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I just re-read my OP here and I must say I'm a bit ashamed of the naivete of only a couple of weeks ago. I've used my Taccom barreled gun for two matches now and it does everything as advertised, and more. The "and more" part is that everyone who has seen it thinks it's the Bee's knees.

As to accuracy I haven't shot groups from a rest yet, but I can easily keep off-hand shots within a two inch circle at fifteen yards. That's plenty good enough for the girls I go with.

Weight is a big plus with this barrel combo, too, allowing you to build light making the gun faster to move. My gun is just over five and a half pounds (without ammo) and it feels like a toy compared to some of the other guns I've tried. It is my opinion that the future of PCC will revolve around ultra-lightweight equipment, and Tim Ubl is on the right track with his products.

 

By-the-way, I load to 1.135 inches and it easily spins in the chamber. 

 

 

 

Edited by MikieM
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9 hours ago, 1911luvr said:

Is anyone having problems with a shorter throat in their Taccom ULW upper? My 100gr loads stick in the leade every time, but the same loads run fine in two of my friends' ULW uppers. I'm about to ream mine but thought I'd see what everyone else has experienced before I go through the extra effort.


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Uhmmmmm.....that should be kind of impossible with our reamer. We have 5 reamers made by the same company, we are presently on the 2nd reamer (use the first one now for ruffing). All of our reamers have a longer than SAAMI spec throat. You would be the first one talking about it be too short. I'd like to see that barrel back here for inspection. Impossible yep, but we are dealing with humans......so I've seen stranger stuff.

 

Are you shooting lead or poly coated bullets?

 

Tim

 

PS........is this a barrel with the aluminum shroud? or one of our first ones with the ventilated steel shroud?

 

Edited by TRUBL
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Mine is short also.  My 1.140 loads for my SS didn't come close to the plunk test with MG 121gr.  But it ended up not making much of a difference since you need to be at <1.130" to work properly with the TF mag ext per TF.  So before I got it reamed I tested my rounds in the TF ext and sure enough, they were too long.  So a new load it was. 

 

I am extremely satisfied with the ULW.  2k rounds and not a hiccup, 1 hole at 15yrds from the bench and the transitions are awesome. Would buy again if building another pcc. 

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Uhmmmmm.....that should be kind of impossible with our reamer. We have 5 reamers made by the same company, we are presently on the 2nd reamer (use the first one now for ruffing). All of our reamers have a longer than SAAMI spec throat. You would be the first one talking about it be too short. I'd like to see that barrel back here for inspection. Impossible yep, but we are dealing with humans......so I've seen stranger stuff.
 
Are you shooting lead or poly coated bullets?
 
Tim
 
PS........is this a barrel with the aluminum shroud? or one of our first ones with the ventilated steel shroud?
 

Mine has the aluminum shroud. I can send it back to you, no problem. It's weird because at least two other guys are running the exact loads (all loaded by the same guy) with their ULWs, without problem. They are poly coated 100gr round nose with a short, fat shoulder loaded to 1.085". I was guessing mine didn't get reamed since this projectile loaded to this length also sticks in most PCC barrels and is right at the edge of tolerance for S&W M&P9 barrels (I have one that fits and one that sticks sometimes).



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Mine is short also.  My 1.140 loads for my SS didn't come close to the plunk test with MG 121gr.  But it ended up not making much of a difference since you need to be at  
I am extremely satisfied with the ULW.  2k rounds and not a hiccup, 1 hole at 15yrds from the bench and the transitions are awesome. Would buy again if building another pcc. 


Accuracy is very impressive with these ULWs. Before I got mine I saw my buddy put 5 rounds into a clover leaf from a bag at 25yds. Between the light swing weight and that kind of accuracy I was immediately sold on it.


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2 minutes ago, TRUBL said:

Yea.....I'd like to see it. Also.....I would NOT run poly coated or lead cast bullets in that barrel. I'll check it when I get it, but I suspect that you also have a HUGE build up inside the tube.

 

 

Are you suggesting only FMJ/TMJ’s for these?

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1 hour ago, Screaminyz said:

Hopefully mine is in a truck somewhere driving down the highway emoji16.png Tim don’t forget my spring and foam hand guard


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done and done....on it's way.....you didn't get a tracking number?????

 

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I did. I thought, "wow, this thing transitions quickly." I noticed more dot movement, but it settles quickly. Being it is essentially a pistol barrel inside a shroud, your minor pistol ammo should have a similar PF. Tune the buffer system to the ammo you'll be using. I'm running some ammo just over the minor PF, and had to go to the Taccom ULW buffer system. 

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20 minutes ago, Screaminyz said:

Got it today ?? and it looks awesome will have the gun completed by EOD. Thanks Tim for all the great products you make and sell.

 

 

Get to work man, we want some video of that thing running tonight!

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On 9/23/2017 at 5:37 PM, OPENB said:

9mm burns it's powder charge in 5-8" of barrel, so a 16" barrel could actually make the bullet slower as it leaves the muzzle, depending on the powder used.

 

You would have to really download the round to a slower round out of a 16" barrel. IME every pistol round I shot out of a PCC chronos faster than out of a 5.25"ish 2011. And ballistics by the inch shows every round they tested didn't get slower until 17".

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8 hours ago, PPGMD said:

 

You would have to really download the round to a slower round out of a 16" barrel. IME every pistol round I shot out of a PCC chronos faster than out of a 5.25"ish 2011. And ballistics by the inch shows every round they tested didn't get slower until 17".

 

Absolutely correct.

I thought all that, "The bullet is slowing down in a 16" barrel", was balderdash, and stuff like, "The powder is all used up in 8", was poppycock.

Bullets By The Inch, has shown otherwise. As a matter-of-fact, the 16" mark is about the point where acceleration begins to decrease.

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2 hours ago, MikieM said:

 

Absolutely correct.

I thought all that, "The bullet is slowing down in a 16" barrel", was balderdash, and stuff like, "The powder is all used up in 8", was poppycock.

Bullets By The Inch, has shown otherwise. As a matter-of-fact, the 16" mark is about the point where acceleration begins to decrease.

 

I think it is possible that both people are partially right.  

 

If we look at the extreme example, the 147gr projectile accelerates an average of 418.5 fps for the first 2 inches.  65fps for the 3rd, 49 for the 4th, 56 for the 5th, then 23, 10 and 7 for the next 3 inches.  From that point on, the bullet is simply maintaining velocity for the remaing 10 inches of barrel.  Each sample was taken with a different shot, so there are shot to shot variations that make the results look odd, but the variances are not important in the overall trend.  The powder has all burned by 5" of barrel and the pressure pushing the bullet is dropping fast.  That does not mean that the pressure is so low that the bullet cannot continue to accelerate slightly, but that the rate of acceleration is dropping off fast.  At some point, the pressure will become so low that the friction of pushing the bullet down the barrel exceeds the energy being exerted by the remaining pressure and the bullet starts to slow down.  In this example the projectile does not pick up any meaningful velocity after about 7" of barrel.  

 

If you look at the other extreme, the 90gr Corbon +P,  you would expect that to have a much larger volume of a much slower powder, but the results are similar.  The acceleration slows dramatically after about 7" of barrel.  It continues to pick up a small amount of speed over the remaining 11 inches, but the powder is clearly burned and the pressure is dropping.  Any velocity gained in the final 4 or 5 inches less than the shot to shot variation.  

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On ‎10‎/‎26‎/‎2017 at 10:12 AM, TRUBL said:

well.....you just need to be aware that you will be needing brush out the tube after you are done shooting.

 

What would happen if you failed to brush out the tube after a few thousand rounds of coated bullets?

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