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concretus

FTF issue with new Diamondback DB-10

29 posts in this topic

Hello, It's been a while; I've been out of the scene and just got back in so I'm making up for lost time!! This has always been an excellent site and maybe you can help...

     I just recently purchased a Diamondback DB-10 carbine with a 16" barrel, mid length gas tube, 7" carbine buffer tube, 2.5" long 3.8oz buffer, and C Products 20rnd mag.. It is basically stock except for a Magpul MOE grip and Surefire ProComp brake. I placed an Aimpoint PRO on top of it with Magpul BUIS and took it to the range today to run it for functionality and break it in... I started to break it in with some Magtech 168gr match cartridges; they were doing very well shooting about 1.5 moa and throwing them about 6' at 2:00....Then I tried some 7.62x51mm Hirtenberger Austrian and South African Surplus and then things went south. The spent case was being extracted and ejected; but it seemed like it was short stroking? (if that is the correct term)the bolt wasn't picking up the next round. It did it every time with both types of that ammo. It also did it with 165gr handloads; although it shot those 1moa, it wasn't picking up the next round. I went back to the MagTech ammo to check and everything went fine. Switched back to the surplus ammo and the same issues. I have a few thousand rounds of Hirt, Port, S.A each and just recently some of that Malaysian surplus that just hit the market and I was hoping to use them in this rifle (along with my FAL and PTK91). Is the buffer spring is too heavy? That spring is the stock one which came with the rifle. Do the make lighter springs? I didn't really want to consider an adjustable gas block. I have an Alex Pro 18" mid length with a scope on it I use for hunting. It runs with any ammo I put through it. I did install a JP polished buffer spring in that one....Has anybody encountered anything like this? Any input would be greatly appreciated....Thanks

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What is the powder charge and bullet type, on the handloads? Are you well lubing the BCG? Like really heavy?

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The buffer spring size and coils? How well was it lubed for break in? Most often I would suggest factory ammo for at least 100 rounds.

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52 minutes ago, Sisco said:

What is the powder charge and bullet type, on the handloads? Are you well lubing the BCG? Like really heavy?

It is 40.5gr of Varget under a Sierra 165gr GK; 2.795" oal.  I just wiped it down with Kroil when I first took it down after I brought it home...

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29 minutes ago, edgecrusher said:

The buffer spring size and coils? How well was it lubed for break in? Most often I would suggest factory ammo for at least 100 rounds.

It is a standard spring. I put it up to a DPMS one I had lying around and it looks similar. Okay, I'll try that..

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2 minutes ago, unforgiven said:

More earl is needed me thinks.

Down here in these parts we spelt it erl...

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12 hours ago, concretus said:

It is 40.5gr of Varget under a Sierra 165gr GK; 2.795" oal.  I just wiped it down with Kroil when I first took it down after I brought it home...

I dunno what cases you're running but that seems light to me. Max load for those pills in Varget is 43 grains at 2.750.

Might try to work it up. 

Take it with a grain a salt. I'm hardly a 308ar guru. Soak it down wit motor oil a repeat. 

Screenshot_20170927-203317.thumb.png.465c7ae0c753c0f38c0202b7fe06cfa7.png

Edited by Boot_Scraper

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5 hours ago, Boot_Scraper said:

I dunno what cases you're running but that seems light to me. Max load for those pills in Varget is 43 grains at 2.750.

Might try to work it up. 

Take it with a grain a salt. I'm hardly a 308ar guru. Soak it down wit motor oil a repeat. 

Screenshot_20170927-203317.thumb.png.465c7ae0c753c0f38c0202b7fe06cfa7.png

I'm using LC -77 Match brass... it may seem a little light but the military brass has less capacity than commercial.... I use 41.0 grains with the same bullet and brass in my Alex Pro 18" midlength with no issues...

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21 hours ago, concretus said:

I just wiped it down with Kroil when I first took it down after I brought it home...

  Kroil is great stuff , but I would use a different Lubricant for break in . I use CLP & others here use Mobil 1 10-30 syn motor oil , there are many Weapons type lubricants out there, both should work & don't be shy with it , try to keep it out of the Chamber & off the Bolt Face  . 

 As said above , Measure the Length & Coil count of the Buffer Spring . We just had an issue with a Buffer Spring with thicker Spring Material , that caused issues , the owner changed to a DPMS Buffer Spring with normal Spring diameter & it corrected the issue . 

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I had a little break in the action so I went to the range this afternoon. After the other day I:
* Took the bolt out, wiped down, oiled it and reinstalled it.
* Removed the stock buffer spring and installed a DPMS LR308 carbine buffer spring.
* I used a 10 Pmag I use for my Alex Pro 18" hunting rifle.

I had a box of Armscorp 308 147gr ball, 1 box of Privi yellow box M80, and 1 box of Portuguese FMN surplus. I ran 1/2 a box of the first two and everything worked fine. BTW the Armscorp shot moa the first five rounds. there was a nice 10 shot wad just under 2". The Privi was not as accurate or consistent. The main thing is that the spent cases were ejecting about 6' away at 3:00....A good sign.... Then I loaded 10 rounds of the Port surplus, crossed my fingers and threw some lead down range...Not one FTF or FTE!!!! Throwing them out in the same location. The point of impact was lower than the other two but grouping like the Armscorp did. I've got some 20rd Pmags ordered and I'll test it again with Hirtenberger, S.A, Austrailian, and Malaysian surplus I have....... Thanks for all your input!!!! How many rounds through it to consider it broken in?

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      The break in is more for the Barrel , there are break in procedures that are used by some , according to the Barrel manufacturers . As far as the Rifle itself ,if your rifle is functioning , its broken in :thumbup: Of course the components will wear in more with a higher round count .

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I ran a few patches through the bore this morning and not much copper came out. Wiped the bolt and inside the upper and erled everything down. I'll try the other surplus ammo I got and hope for the best.....that will be the real test for that rifle...

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    After taking it out again, trying all the different surplus ammo I have, and some hand loads (LC brass, WLR primer, 42.5gr IMR-4064, Sierra 165 GK), the Hirtenberger Austrian surplus continued to short stroke; even with the swapped buffer spring and Pmag. Overall, I'm satisfied... I'll just save that ammo for my FAL. That's what it was made for anyway...BTW the hand-loads performed well with a 1.5moa 5 shot group. Definitely hunting worthy...Shooting was done off a bench w/ rest at 100yds. Optic was an Aimpoint PRO. Considering a 2.5x or 3x prism type optic....

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1 hour ago, concretus said:

    After taking it out again, trying all the different surplus ammo I have, and some hand loads (LC brass, WLR primer, 42.5gr IMR-4064, Sierra 165 GK), the Hirtenberger Austrian surplus continued to short stroke; even with the swapped buffer spring and Pmag. Overall, I'm satisfied... I'll just save that ammo for my FAL. That's what it was made for anyway...BTW the hand-loads performed well with a 1.5moa 5 shot group. Definitely hunting worthy...Shooting was done off a bench w/ rest at 100yds. Optic was an Aimpoint PRO. Considering a 2.5x or 3x prism type optic....

 Magnification should shrink group size , as will a good Trigger . :thumbup:

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Posted (edited)

On 9/28/2017 at 0:16 AM, concretus said:

I'm using LC -77 Match brass...

That brass is 40 years old right now, as we type up stories about this.  It really is.  Rule out 40-year old brass, as your first reloading equation. Match brass or not.  Seriously.

 

Jimmy Carter was president when that brass was manufactured.

Edited by 98Z5V

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On ‎10‎/‎8‎/‎2017 at 0:00 AM, 98Z5V said:

That brass is 40 years old right now, as we type up stories about this.  It really is.  Rule out 40-year old brass, as your first reloading equation. Match brass or not.  Seriously.

 

Jimmy Carter was president when that brass was manufactured.

Actually that brass has been more consistent in weight and performs better than some of the newer LC.....I picked up a bag of 500 LC-12, and had a couple with spilt necks after 2 reloadings.....

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1 hour ago, concretus said:

Actually that brass has been more consistent in weight and performs better than some of the newer LC.....I picked up a bag of 500 LC-12, and had a couple with spilt necks after 2 reloadings.....

I am using some Indian M-80 brass from 1975, and it is consistently good. I just won't reload it more than once.

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1 hour ago, concretus said:

I picked up a bag of 500 LC-12, and had a couple with spilt necks after 2 reloadings.....

  Annealing your Brass ?

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28 minutes ago, concretus said:

 

yes

 How are you confirming the brass is getting the proper tempering temperature ?

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3 hours ago, survivalshop said:

 How are you confirming the brass is getting the proper tempering temperature ?

I don’t...I turn the case while up in the flame 

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