Taccom Delayed Blowback Recoil System

[Ontos]

Mine should be here today... Love to get this all dialed in before the New Mexico Sectional. 

[Blockader]

What is the required size of the hole in the back of the bolt? 

[TRUBL]

39 minutes ago, Blockader said:

What is the required size of the hole in the back of the bolt? 

.620" is good to go.........if you get into the size of the hole on the JP bolt, then you need to remove the front keeper and run it with a detent pin. The absolute smallest hole can be no smaller than .525" diameter.

Tim

[Blockader]

28 minutes ago, TRUBL said:

.620" is good to go.........if you get into the size of the hole on the JP bolt, then you need to remove the front keeper and run it with a detent pin. The absolute smallest hole can be no smaller than .525" diameter.

Tim

 

I run a New Frontier bolt which has a removable solid rear weight. They make a pass through adaptor that has a inner diameter of .53", I reckon I'll give it a shot when I get the bones:

 

https://www.newfrontierarmory.com/shop/ar-9-bcg-adapter-weight/

[cecil]

got my Taccom Delayed Blowback Recoil System Saturday... took the weight out of the bolt..  loaded some 115gr ammo and made a trip to the range... lowest PF  I  loaded was 115 .. will load some lower PF and test again Tuesday..   found 115 PF  a bit on the snappy side...…  the saga continues...

[TRUBL]

1 hour ago, cecil said:

got my Taccom Delayed Blowback Recoil System Saturday... took the weight out of the bolt..  loaded some 115gr ammo and made a trip to the range... lowest PF  I  loaded was 115 .. will load some lower PF and test again Tuesday..   found 115 PF  a bit on the snappy side...…  the saga continues...

Don’t confuse snappy with more.....the system is going to be faster. Recoil is less and thebtell tale is the amount of dot bounce which should be way less

Tim

[LowSpeedHighDrag]

2 hours ago, cecil said:

got my Taccom Delayed Blowback Recoil System Saturday... took the weight out of the bolt..  loaded some 115gr ammo and made a trip to the range... lowest PF  I  loaded was 115 .. will load some lower PF and test again Tuesday..   found 115 PF  a bit on the snappy side...…  the saga continues...

 

What powder did you use?

 

[HoMiE]

If the upper receiver and receiver extension are made out of aluminum, what do the magnets attract too? 

[sweatpants]

@TRUBL I got the new buffer installed, bolt slug from the Extreme bolt removed and buffer detent removed, but I have a question before shaking it out this week.  The brass part of the new buffer is peeking out past the front of the buffer extension area of the lower but turning the buffer tube another turn wouldn’t allow the upper to mount.  

 

Is this an issue?  It looks like the rear of the bolt carrier and the front of the buffer would contact once shut but I have no way of visually confirming.

[Bwillis]

5 hours ago, HoMiE said:

If the upper receiver and receiver extension are made out of aluminum, what do the magnets attract too? 

 

They have a metal core the magnets pull on. To me it looks like a si buffer, but inside of the spring there is a magnet slider. 

[TRUBL]

7 hours ago, sweatpants said:

@TRUBL I got the new buffer installed, bolt slug from the Extreme bolt removed and buffer detent removed, but I have a question before shaking it out this week.  The brass part of the new buffer is peeking out past the front of the buffer extension area of the lower but turning the buffer tube another turn wouldn’t allow the upper to mount.  

 

Is this an issue?  It looks like the rear of the bolt carrier and the front of the buffer would contact once shut but I have no way of visually confirming.

So you push back the brass and close the upper......pretty sure at that point you’ll be contacting the bolt.....and that’s a good thing.

[cecil]

17 hours ago, LowSpeedHighDrag said:

 

What powder did you use?

 

Sport PIstol  

[RaylanGivens]

21 hours ago, cecil said:

got my Taccom Delayed Blowback Recoil System Saturday... took the weight out of the bolt..  loaded some 115gr ammo and made a trip to the range... lowest PF  I  loaded was 115 .. will load some lower PF and test again Tuesday..   found 115 PF  a bit on the snappy side...…  the saga continues...

 

115 powerfactor ammo was snappy?

 

Assume that was for Steel Challenge?

 

[cecil]

15 hours ago, RaylanGivens said:

 

115 powerfactor ammo was snappy?

 

Assume that was for Steel Challenge?

 

Yes  .. Steel Challenge …    .. I shot 4 - 6 shot Bill drills with the prementioned ammo... was able to keep it on a 12"x14" target... but.. the shots were spread out... my previous load with the same PCC I was able to shoot 6 shot   Bill drills and cover all the shots with the palm of my hand.. so I think more experimenting  will be required..

Edited July 10, 2019 by cecil

[sweatpants]

I got a chance to test the DBRS, I'm a fan so far.  I dropped a couple quarters in behind it because my brass piece didn't stick out very much and it seemed to be better.  

 

I'll get a chance to shake this out at USPSA twice this weekend and report back with more feedback.  

 

https://instagram.com/stories/khoi.shoots/2086436034224232099?igshid=1g10netz3z630

Edited July 12, 2019 by sweatpants

[TRUBL]

35 minutes ago, sweatpants said:

I got a chance to test the DBRS, I'm a fan so far.  I dropped a couple quarters in behind it because my brass piece didn't stick out very much and it seemed to be better.  

 

I'll get a chance to shake this out at USPSA twice this weekend and report back with more feedback.  

 

https://instagram.com/stories/khoi.shoots/2086436034224232099?igshid=1g10netz3z630

So you see a faster impulse and......the dot bounce looks like almost nothing!!

[Wvaughn7]

Got the system in yesterday and installed and tested today. Filmed in slow-no and cycle speed went from .12 to .085 seconds from first bolt movement to back in battery. The dot stays nice and still as well. Still some playing to do but impressed so far. 

[sweatpants]

I have around 700 rounds on this buffer now with a short function test and 2 USPSA matches. I'm going to have one more match and shake down practice before Area 4.  It's definitely a more stiffer recoil impulse but I think the dot settles a predictably.  I had one unintended bump fire but I'm not paying it much attention unless it happens more often.  

 

 

[LowSpeedHighDrag]

1 hour ago, sweatpants said:

I have around 700 rounds on this buffer now with a short function test and 2 USPSA matches. I'm going to have one more match and shake down practice before Area 4.  It's definitely a more stiffer recoil impulse but I think the dot settles a predictably.  I had one unintended bump fire but I'm not paying it much attention unless it happens more often.  

 

 

What load are you using (powder & bullet)?

[sweatpants]

2 minutes ago, LowSpeedHighDrag said:

 

What load are you using (powder & bullet)?

 

HS-6 and 124gr PD JHPs.

[7ender]

For how much of a "game changer" this was supposed to be, I haven't really seen many reports on here.  Not saying this is good or bad...just had expected to hear more feedback.

 

Anyone else shot theirs yet? 

[Ontos]

1 hour ago, 7ender said:

For how much of a "game changer" this was supposed to be, I haven't really seen many reports on here.  Not saying this is good or bad...just had expected to hear more feedback.

 

Anyone else shot theirs yet? 

 

I decided to do a whole new build for this... Should have everything together by next weekend. 

[RaylanGivens]

Since the premise of the Delayed Blowback Recoil System is to hold the bolt closed longer...  Would that increase the powerfactor of a given load?  Seems like delaying the gas blowback would force more of the energy down the barrel and increase the powerfactor.

 

Seems like that would help lower recoil...  Because you could move to a lighter load and maintain the same powerfactor.

 

[sweatpants]

21 minutes ago, RaylanGivens said:

Since the premise of the Delayed Blowback Recoil System is to hold the bolt closed longer...  Would that increase the powerfactor of a given load?  Seems like delaying the gas blowback would force more of the energy down the barrel and increase the powerfactor.

 

Seems like that would help lower recoil...  Because you could move to a lighter load and maintain the same powerfactor.

 

 

It's not my experience that delaying the blowback resulted in higher velocity given the same load.  The recoil impulse is increased because the bolt carrier mass is lighter given the same load.

[sweatpants]

I shot Area 4 over the weekend and the buffer performed without any catastrophic issues.  However, I did bump fire a number of times on different stages and because of the increased cyclic rate I turned a few heads.  In general I don't want to send any more shots than the ones I really wanted to send so I may go back to the 3-stage buffer with marginally worse dot performance.