PDA

View Full Version : DTA HTI in 50DTC


atolax25
09-21-2013, 1:59 PM
So I was thinking of getting a DTA HTI and converting it to 50DTC. Is it possible/legal to order the chassis (which has the serial number on it) and send it to my FFL and simultaneously order the 50BMG conversion kit, have it sent to me personally and then just get it converted? I just want to avoid any of that constructive possession nonsense...

BigBamBoo
09-21-2013, 2:30 PM
I did not have a 50, but when I ordered my DTA, I did just that. Had the chassis sent to my FFL and had the mags, bolt, and barrels sent directly to me.

Now....I am not to sure I would have a 50BMG "conversion kit" in the same location as the the chassis. There are a few smith's that do barrels for the DTA rifles and all you need is the barrel extension, bolt, and mag. I would play it safe and just send the barrel extension to whoever is going to chamber your DTC barrel.

brando
09-21-2013, 3:04 PM
They aren't going to be making a DTC conversion kit any time soon, however you could pretty easily have a smith familiar with the DTA platforms spin-up a barrel for you. Here's what you'd have to do:

1. order an HTI chassis and have it sent to your FFL
2. order an HTI barrel extension, .50BMG brake, bolt and magazine and have that shipped to you.
3. once you've DROSd your chassis send the whole package to a smith that's familiar with the DTA platforms (ask DTA for recommendations)

Short Action Customs is one of the few shops that is really familiar with the SRS and makes lots of conversions, however the dimensions on the HTI are different so you'd have to confirm with them that they can do the conversion.

A good smith with the barrel schematics (supplied in the armorer's toolkit) should be able to make up a barrel for you. However, it helps to have an example on hand, in which case ordering the .375CT conversion with the chassis would be a huge benefit ;)

I've had a number of conversions made for my SRS by my local smith, but it was easier for him because he could refer to my two factory barrels for examples of the unique barrel tenon as well as the barrel schematics.

A call to DTA would be a good first step.

atolax25
09-22-2013, 8:36 PM
Would it be possible to have the 50bmg barrel they supply converted to a 50dtc? Or would I need to get a completely new barrel made for it? I'm not entirely sure how converting them would work.

brando
09-22-2013, 8:50 PM
Getting a .50BMG barrel into CA could potentially be a problem because as soon as you install it in the chassis you're breaking the 2005 .50BMG ban. Perhaps the barrel on its own isn't a problem, I don't know for sure? The main difference between .510DTC and .50BMG is a steeper shoulder angle and slightly shorter case length, but I'm not 100% sure if those differences are too much to prevent a chamber conversion? If you're serious about this, talk to a smith (like I recommended above). You could also buy a .510DTC reamer from PTG and try to sweet talk DTA into cutting a barrel for you, but considering their current backlog I wouldn't expect you to get a positive answer.

Personally, I would go for the .375CT conversion as it's the best performing ELR cartridge at the moment, hands down.

ar15barrels
09-22-2013, 8:50 PM
As long as the barrel is not chrome lined, I could take the BMG barrel apart and set it back and rechamber to DTC.
All I would need sent to me is the barrel and bolt.

ar15barrels
09-22-2013, 8:52 PM
Getting a .50BMG barrel into CA could potentially be a problem because as soon as you install it in the chassis you're breaking the 2005 .50BMG ban. Perhaps the barrel on its own isn't a problem, I don't know for sure?

There is no "constructive possession" of California Assault Weapons unless a DA decides he has a case...

brando
09-22-2013, 8:52 PM
Ah yes, you could definitely rechamber it by essentially cutting off the existing chamber ;)

Actually scratch that. The way the DTA barrels are designed, you can't remove too much of the chamber without affecting the interface with the chassis. For .50BMG to .510DTC may not have to set it back too much though.

ar15barrels
09-22-2013, 8:55 PM
Ah yes, you could definitely rechamber it by essentially cutting off the existing chamber ;)

It should only need to be set back about 3/16" to 1/4" to "clean out" the BMG shoulder with the DTC shoulder.
3-4 turns would do.

brando
09-22-2013, 8:56 PM
Then that's probably fine.

There's your answer OP - DROS a chassis and buy a .50BMG conversion kit separately and take it over to Randall to recut the chamber.

ar15barrels
09-22-2013, 10:00 PM
Then that's probably fine.

There's your answer OP - DROS a chassis and buy a .50BMG conversion kit separately and take it over to Randall to recut the chamber.

I just went and looked at the drawings.
It theoretically takes 0.144" of chamber setback for the DTC reamer to completely "clean out" a BMG chamber.
Assuming a 16tpi thread spec inside the SRS barrel extension, 2.5 turns will do it.
If there are barrel markings to keep timed correctly, then we go 3 full turns of setback...

brando
09-22-2013, 10:11 PM
The profile on the DTA barrel tenon is kind of particular. Retiming the barrel extension would have to be consistent so that it indexes correctly to the barrel locking notch cut on the bottom towards the front edge of the tenon. The HTI could be different but as far as I recall, all of the SRS barrel threads are 24tpi.

ar15barrels
09-22-2013, 10:15 PM
The profile on the DTA barrel tenon is kind of particular. Retiming the barrel extension would have to be consistent so that it indexes correctly to the barrel locking notch cut on the bottom towards the front edge of the tenon. The HTI could be different but as far as I recall, all of the SRS barrel threads are 24tpi.

The barrel locking notch was just a notch where the lock screw crosses the barrel right?
If so, that notch will move back as the barrel is shortened so a NEW notch will get cut.
In that case, it's best to rotate the OLD notch purposely OUT of index so the user does not try to install the barrel with the OLD notch as that would have the barrel sitting 5/32" too far forward and the locking lugs of the extension would not be inline with the bolt lugs.
I have had an SRS barrel in my hand, but not an HTI...

brando
09-22-2013, 10:42 PM
My point is that the notch is pretty far forward, so if you essentially shorten the tenon a bit when re-cutting the chamber and re-installing the barrel extension, there might not be enough of the front portion of the tenon to cut another notch. The OD of the tenon is quite large, then it immediately transitions into the intended barrel profile.

atolax25
09-23-2013, 12:17 AM
Thanks for all the advice everyone! I'll put one on order and work from there. Good to know you'd be willing to help, Randall. I was thinking of contacting you about this anyway.

BigBamBoo
09-23-2013, 7:40 AM
Here are the drawings for the DTA .338 and smaller barrel. I thought I had the drawings for the 50 as well and will keep looking for them.

http://img822.imageshack.us/img822/3417/gwt0.jpg (http://imageshack.us/photo/my-images/822/gwt0.jpg/)

http://img853.imageshack.us/img853/4162/vmre.jpg (http://imageshack.us/photo/my-images/853/vmre.jpg/)

ar15barrels
09-23-2013, 9:20 AM
Here are the drawings for the DTA .338 and smaller barrel. I thought I had the drawings for the 50 as well and will keep looking for them.

http://img853.imageshack.us/img853/4162/vmre.jpg (http://imageshack.us/photo/my-images/853/vmre.jpg/)

Stan-

There is no locking notch location called out on that print.
I thought I remember there being a locking notch milled in the barrel forward of the extension.
Can you take a picture of the bottom and top of the barrel shank while it is out of the receiver?

BigBamBoo
09-23-2013, 9:23 AM
Your right. There is a locking/alignment notch. I no longer own the DTA SRS so I am of no help on that. Sorry.

Take care, Stan

mrkubota
09-23-2013, 9:43 AM
... from this picture, it looks like there will be enough clearance to mill another notch even with setback for the DTC conversion...

http://www.deserttacticalarms.com/dta-hti-conversion-kit.html

Randall.... I've got a couple of DTC reamers here you can borrow too if you'd like. (Manson and JGS)

//Ben

BigBamBoo
09-23-2013, 10:39 AM
Thinking back on it...I am pretty sure the notch is on the barrel extension and not on the barrel.
And if memory serves me, it is on the bolt side of the extension. If not, then the barrel would not be able to seat in the chassis. There would need to be a channel in the barrel extension to allow it to seat if the notch was anywhere else.

I think that is why it is not shown on the barrel drawings.

Then again it has been awhile since I had the DTA.

brando
09-23-2013, 12:20 PM
http://shortactioncustoms.com/wp-content/uploads/2013/04/IMG_5666.jpg

Nah, it's towards the front of the tenon away from the barrel extension.

BigBamBoo
09-23-2013, 12:31 PM
I had the first gen model, and I think that was one of the "modifications" they did on the 2nd+ gen models. I know for sure mine did not have that on the barrels I had.

Take care, Stan

brando
09-23-2013, 12:36 PM
I have a first Gen model too, but as far as I know only the barrel extension changed between the 1st and 2nd revisions.

mrkubota
09-23-2013, 12:37 PM
... that's interesting... from the pics linked at their website, the barrels appear to have been notched on the extension a bit less than halfway up.

Here's a zoomed in version where it's a little easier to see the notches on the barrel extensions:

http://www.daplane.com/50bmg/50dtc/DTA_HTI_BBLS.jpg

BigBamBoo
09-23-2013, 2:09 PM
Well I am at a loss. I had the .243 and two .308 barrels and none had that notch.
When I would "drop" the barrel in, I would rotate it until the notch in the barrel extension would "lock in" on a little pin that fit into the notch.

Again, my rifle was I think the 10th or so they made. It had to go back a couple of times. First was for trigger issues.

They sent me a armorers kit along with those drawings because we were going to make up some barrels in 6XC and 6SLR, but never got around to it.

Ended up selling the rifle and moving onto other things. Fun platform for sure and great for multi-caliber shooting. I just like to try new things.

You still in the land of the kiwi's?

Take care, Stan

I have a first Gen model too, but as far as I know only the barrel extension changed between the 1st and 2nd revisions.

brando
09-23-2013, 3:21 PM
My SRS comes from the same first run. Regardless, the HTI probably has some slight differences.

Yep, been here in New Zealand for almost 3 years now, got my SRS and SPR over here last year and the first thing I did was make suppressors for them. It's a unique feeling knowing that here I can either walk into a store and buy a suppressor or just build one myself (design on Solidworks and take to an engineering shop); no paperwork, no wait, no nothing.

ar15barrels
09-23-2013, 5:52 PM
Yep, been here in New Zealand for almost 3 years now,

Are you ever moving back here?

brando
09-23-2013, 7:30 PM
Hard to say. I have family there obviously and my wife is from LA, but I really like it here in NZ for a lot of reasons. The biggest roadblock for me to return to the States is the lack of work for me. The movie studios have crushed the visual effects industry in the US, particularly in CA, forcing more and more of the work to be done in Vancouver, London, Australia and Canada (plus the one studio here in NZ). A lot of the big companies like ILM are still hiring, but in places like the above, so I would likely be looking at starting a 3rd career if I moved back. Which isn't such a bad idea as I have a GI Bill that needs to be used in the next five years and it could pay for a few years at Trinidad or Yavapai ;)