Muzzle flip due to bcg travel?

[mstamper]

Saw a video today that made me think about how much movement of the muzzle / dot is due to the bcg traveling farther than it needs to cycle the weapon over the actual bullet / gases exiting the weapon.

 

I have read several posts here with users saying to put quarters or washers or even water hose gaskets to shorten the bcg travel.

 

I'm wondering if the use of a buffer recoil system like the jp or the mbx or blitzkrieg is the best choice over just adding something to the end of buffer to control recoil?

 

Or what about a combination of the buffer system AND reducing travel via stacking the end of the tube?

 

I recently put the blitzkrieg system in my pc and have noticed a softer recoil but I am now noticing that it appears that the weapon is slower to reset the trigger.

 

Would shortening the bcg travel to go just past the bolt lock allow the trigger to reset and the bcg return to battery quicker hence allowing for faster follow up shots and better controled recoil since the entire mass is moving less?

 

If one does shorten the bcg travel, does a recoil buffer system even come into play or is all recoil then being handled by the buffer spring alone?

 

Thanks,

Mark

 

 

Sent from my LG-H872 using Tapatalk

 

 

[Garmil]

2 minutes ago, mstamper said:

 

Saw a video today that made me think about how much movement of the muzzle / dot is due to the bcg traveling farther than it needs to cycle the weapon over the actual bullet / gases exiting the weapon.

 

I have read several posts here with users saying to put quarters or washers or even water hose gaskets to shorten the bcg travel.

 

I'm wondering if the use of a buffer recoil system like the jp or the mbx or blitzkrieg is the best choice over just adding something to the end of buffer to control recoil?

 

Or what about a combination of the buffer system AND reducing travel via stacking the end of the tube?

 

I recently put the blitzkrieg system in my pc and have noticed a softer recoil but I am now noticing that it appears that the weapon is slower to reset the trigger.

 

Would shortening the bcg travel to go just past the bolt lock allow the trigger to reset and the bcg return to battery quicker hence allowing for faster follow up shots and better controled recoil since the entire mass is moving less?

 

If one does shorten the bcg travel, does a recoil buffer system even come into play or is all recoil then being handled by the buffer spring alone?

 

Thanks,

Mark

 

 

Sent from my LG-H872 using Tapatalk

 

 

 

If you shorten the travel the buffer is still going to bottom out on something. For the spring alone to do the work it would have to be a custom heavy spring and wouldn't be as consistent I would guess.

[stick]

The Taccom 3 stage buffer actually limits the travel of the BCG.  First picture is the assembled Buffer.  The second picture is what actually slows the travel of the BCG.  

 

 

[MikieM]

The velocity of the bolt/buffer in the AR9 is dependent upon the pressure behind the bullet, or simply how hot your load is. The more powder used the stronger the push. Barrel length comes into play here, as well, allowing more time for that push before the bullet exits the barrel.

If you want less recoil then reduce your load. Further tuning can then be accomplished by finding the best spring, or recoil system, that suits the load you have chosen. 

To me the best load would be one that made a PF of 130. That would be the start point.

Edited February 11, 2018 by MikieM

[Aircooled6racer]

Hello: Testing is the only way to see what you like. I don't like the really short stroke in a blowback PCC. I find it harsh but it does reset the trigger quickly. I find my splits are just as quick and more accurate for me with the longer stroke and lighter weight of the buffer and spring. I have used a timer and hits on target to prove this to myself over and over again. For me a soft shooter is faster than a quick cycling PCC. This is what makes shooting PCC so much fun with all these different setups. Thanks, Eric

[mstamper]

The velocity of the bolt/buffer in the AR9 is dependent upon the pressure behind the bullet, or simply how hot your load is. The more powder used the stronger the push. Barrel length comes into play here, as well, allowing more time for that push before the bullet exits the barrel.
If you want less recoil then reduce your load. Further tuning can then be accomplished by finding the best spring, or recoil system, that suits the load you have chosen. 
To me the best load would be one that made a PF of 130. 

I'm shooting a 16" barrel 9mm diamondback pcc with a birdcage on the front. I've put a blitzkrieg buffer system with a jp 308 carbine spring and a hiperfire 24 3g trigger and a burris ff3 optic.

I shoot freedom munitions 124 grn plated rounds at 1061 fps at the muzzle of a 9mm pistol.

The recoil is much lighter with the blitzkrieg system. I don't feel the buffer bottoming out. I still have some dot / muzzle movement that I'm not sure if it is from the round leaving the gun or from the bcg moving a lot.

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[Flatland Shooter]

1 hour ago, Aircooled6racer said:

This is what makes shooting PCC so much fun with all these different setups. Thanks, Eric

 

And its so easy to do.  For a few bucks you can switch out almost any part and get your PCC to feel a bit different.  Then its your decision as to whether or not the change is for the better or worse.

 

I can't say what will work best for you.  What I can do is share what is currently working for me. 

 

For USPSA I'm shooting a 16" light weight barrel with a Miculek style comp.  The comp is there to get a bit more noise back to the timer and it seems to work.  For the bolt, I'm back using a stock bolt that weighs 14.9 oz.  My buffer weighs 5.2 ounces and the spring  is a standard .223 carbine spring with $2.75 of quarters behind the spring.  Pretty simple.

 

For ammo, this season I've bumped up the PF to around 145 with 147 gr plated bullets.  The recoil may be a bit stouter than the load I used last year, but along with a minor change in technique, the time and accuracy of my splits have significantly improved.

 

For the minor change in technique, watch this YouTube video.    

 

 

 

Good luck.

Edited February 11, 2018 by Flatland Shooter

[MikieM]

7 minutes ago, mstamper said:

I'm shooting a 16" barrel 9mm diamondback pcc with a birdcage on the front. I've put a blitzkrieg buffer system with a jp 308 carbine spring and a hiperfire 24 3g trigger and a burris ff3 optic.

I shoot freedom munitions 124 grn plated rounds at 1061 fps at the muzzle of a 9mm pistol.

The recoil is much lighter with the blitzkrieg system. I don't feel the buffer bottoming out. I still have some dot / muzzle movement that I'm not sure if it is from the round leaving the gun or from the bcg moving a lot.

Sent from my LG-H872 using Tapatalk
 

 

Sounds like a winner. 

I'd say shoot it a while to get used to how it feels. 

[MikieM]

Flats, is correct. These guns are very individualized. I'll bet there aren't two of them the same in the whole bunch of us.

They even take on some of the persona of their owners. Like when I'm shooting mine it feels like I'm going a hundred miles a hour. In reality my split times are about four and a half minutes. 

[BigBamBoo]

This right here for me as well. I sometimes feel like I am really moving. Then I review the video and I look like a dancing bear from the Russian circus!

 

But I have fun and will continue to do it until it is not fun anymore.

[Flatland Shooter]

I wish I could move as well as a dancing bear.  RO's have threatened to time me with sun dials.

 

I built a "BigBamBoo" gun with parts I got for Christmas (Taccom ULW barrel + Blitzkrieg Buffer + assorted buffer springs).   It will take some getting used to.  It reacts much differently than my other AR-9's.  At this point it is not my favorite gun for matches but it is my most accurate AR-9 at distances of 75 yards or more.

[mstamper]

15 hours ago, Aircooled6racer said:

Hello: Testing is the only way to see what you like. I don't like the really short stroke in a blowback PCC. I find it harsh but it does reset the trigger quickly. I find my splits are just as quick and more accurate for me with the longer stroke and lighter weight of the buffer and spring. I have used a timer and hits on target to prove this to myself over and over again. For me a soft shooter is faster than a quick cycling PCC. This is what makes shooting PCC so much fun with all these different setups. Thanks, Eric

Eric,

I fully understand that testing is the only way to see what works for one person over another. I am looking for data that others have done and their impressions so that I can, at least, have a starting point for testing. I guess my ideal situation is a short stroke of the bcg AND a soft felt recoil. Is that a utopian ideal? that is why we buy gadgets and doodads and hand load to tweak our systems to find that ideal combination.

 

Before I bought my blitzkrieg buffer system and spring I must have ready every post here about every buffer system and combination other shooters here tried. I made my decision based on my current bolt. The bolt in the diamondback pcc has a solid slug weight that extends on the end of the bolt. Other bolts have the weight inside of the bolt. I learned that the JP system needs a bolt that you can remove the weight slug to allow the bolt to travel properly with that system. I also chose the blitzkrieg because I did not want to deal with spending money on weight rings and the umpteen possible configurations that the jp buffer system had. I am happy with the blitzkrieg and 308 carbine spring even though I feel that the bolt is now moving a bit slower now. That, along with watching a youtube video about bolt travel having some effect on muzzle flip, is what started this thread.

 

I did the same process before I bought my hiperfire 24 3g trigger to replace the mil spec trigger that came with the gun. Again, price dictated which hiperfire trigger I bought. I like flat blade triggers, I have an APEX flat trigger on my Q5 match. I just could not justify the additional cost to go from a curved trigger over the flat blade. 

 

On another side, I see that you are in Alpharetta. I am in Peachtree Corners. Where do you shoot around town? I shoot the USPSA weekly match at Range Guns and Safes on pleasantdale road with the GPSL guys. I also shoot NAAS matches in Cumming at Bullseye up there. I shoot an occasional GADPA match at Norcross guns and range on PIB at Medlock Bridge road. I would love to find some more indoor USPSA matches till the weather improves. Do you shoot any outdoor matches? if so, where?

 

Thanks,

Mark

[MikieM]

2 hours ago, Flatland Shooter said:

I wish I could move as well as a dancing bear.  RO's have threatened to time me with sun dials.

 

I built a "BigBamBoo" gun with parts I got for Christmas (Taccom ULW barrel + Blitzkrieg Buffer + assorted buffer springs).   It will take some getting used to.  It reacts much differently than my other AR-9's.  At this point it is not my favorite gun for matches but it is my most accurate AR-9 at distances of 75 yards or more.

 

My first wife looked a lot like a dancing bear.

As a matter-of-fact, when ever we would go out to a nightclub we'd always come home with our pockets full of quarters.  

 

But, like Big said. I do it 'cause it's fun. Lord knows I'm not making any money at it.

Edited February 11, 2018 by MikieM

[Aircooled6racer]

4 hours ago, mstamper said:

Eric,

I fully understand that testing is the only way to see what works for one person over another. I am looking for data that others have done and their impressions so that I can, at least, have a starting point for testing. I guess my ideal situation is a short stroke of the bcg AND a soft felt recoil. Is that a utopian ideal? that is why we buy gadgets and doodads and hand load to tweak our systems to find that ideal combination.

 

Before I bought my blitzkrieg buffer system and spring I must have ready every post here about every buffer system and combination other shooters here tried. I made my decision based on my current bolt. The bolt in the diamondback pcc has a solid slug weight that extends on the end of the bolt. Other bolts have the weight inside of the bolt. I learned that the JP system needs a bolt that you can remove the weight slug to allow the bolt to travel properly with that system. I also chose the blitzkrieg because I did not want to deal with spending money on weight rings and the umpteen possible configurations that the jp buffer system had. I am happy with the blitzkrieg and 308 carbine spring even though I feel that the bolt is now moving a bit slower now. That, along with watching a youtube video about bolt travel having some effect on muzzle flip, is what started this thread.

 

I did the same process before I bought my hiperfire 24 3g trigger to replace the mil spec trigger that came with the gun. Again, price dictated which hiperfire trigger I bought. I like flat blade triggers, I have an APEX flat trigger on my Q5 match. I just could not justify the additional cost to go from a curved trigger over the flat blade. 

 

On another side, I see that you are in Alpharetta. I am in Peachtree Corners. Where do you shoot around town? I shoot the USPSA weekly match at Range Guns and Safes on pleasantdale road with the GPSL guys. I also shoot NAAS matches in Cumming at Bullseye up there. I shoot an occasional GADPA match at Norcross guns and range on PIB at Medlock Bridge road. I would love to find some more indoor USPSA matches till the weather improves. Do you shoot any outdoor matches? if so, where?

 

Thanks,

Mark

Mark :Big Woods Goods has an USPSA indoor match every Thursday. I like shooting outdoors mostly at Cherokee, South River, River Bend, Griffin, and CMP in Alabama. I would try a 223 spring with your Blitzkrieg buffer and remove the weight in your bolt. Load 124grain bullets to 131-134PF. Thanks, Eric

[L9X25]

Mark,

 

Look at it this way ... if you have some 115gr bullets loaded to 130pf and some 160gr bullets loaded to 130pf, which ones have more recoil?   

Trick question right?  Technically they both have the same energy so they should have the same recoil, but they feel different.  The reason is that the 160's recoil impulse is ~40% longer than the impulse of the 115's so the same energy spread over a longer period of time feels softer, even though the total energy conveyed is the same.  

 

Shortening the stroke on the bolt has a similar effect, you have to dissipate the energy transferred to the bolt and the longer the bolt travels, the more time you can spread the recoil over.  If you are outrunning your bolt, you might consider short stroking to speed up that process, at the cost of a more violent recoil action.  I am not aware of anyone outrunning the bolt, so I see no benefit to reducing the stroke.  

 

Edited February 12, 2018 by L9X25

[Flatland Shooter]

19 minutes ago, L9X25 said:

I see no benefit to reducing the stroke.  

 

 

Only benefit I know of is protecting the bolt catch. The theory is the shorter stroke does not give the bolt enough time to build up momentum before it comes to the bolt catch to break it. So far its worked for me.

Edited February 12, 2018 by Flatland Shooter

[L9X25]

4 minutes ago, Flatland Shooter said:

 

Only benefit I know of is protecting the bolt catch. The theory is the shorter stroke does not give the bolt enough time to build up momentum before it comes to the bolt catch to break it. So far its worked for me.

 

I cannot speak to bolt catch longevity, I have only run my gun dry a few times to test the LRBHO and have not broken one yet.  I have the Blitzkrieg buffer and do not think that I have more than 1/4" of travel beyond the latch.

[msg73]

There are two main recoil impulses:  1) when your bolt/buffer goes back and bottoms out at end of the buffer tube or quarters/spacer and 2) when your bolt slams forward at the end of the firing cycle. 

 

I agree that the rearward recoil impulse would be lessened with a longer stroke but that extra length would also enable the bolt to travel faster in the forward stroke. This is where the feel is very subjective relative to the shooter.  I, like many here, have tried different setups and I prefer a shorter stroke with a lighter 223 spring.  Like Eric, I use hits on paper and a timer to be the judge as subjective feelings could fool you into thinking a particular setup is better because it feels better but in reality, it may be slower and less accurate. 

[L9X25]

3 hours ago, msg73 said:

There are two main recoil impulses:  1) when your bolt/buffer goes back and bottoms out at end of the buffer tube or quarters/spacer and 2) when your bolt slams forward at the end of the firing cycle. 

 

I agree that the rearward recoil impulse would be lessened with a longer stroke but that extra length would also enable the bolt to travel faster in the forward stroke. This is where the feel is very subjective relative to the shooter.  I, like many here, have tried different setups and I prefer a shorter stroke with a lighter 223 spring.  Like Eric, I use hits on paper and a timer to be the judge as subjective feelings could fool you into thinking a particular setup is better because it feels better but in reality, it may be slower and less accurate. 

 

(1) If the bolt bottoms out hard on end of the buffer tube, you went too light on the spring.  

 

(2) A spring stores energy and gives it back, regardless of the travel distance.  If you short stroke, you need a heavier spring to keep #1 above from happening.  The heavier spring will accelerate the buffer to same speed in a shorter distance, that a softer spring will accelerate it to over a longer distance.  The same amount of work is being done, in both directions, the only thing that is changing is how long the energy is spread over.  Short stroking compresses the time over which the energy is transferred to the shooter. 

 

To me feel is secondary, I tune the weights/springs based on what the target tells me is happening.  I have seen where 2 set-ups that feel similar, yet give significantly different results on the target.  It is entirely possible that shortening the stroke makes the rifle more harsh, but give it more time to settle before the next shot and makes it shoot tighter.  That is something that I could understand, but it would not "feel" better.  

[mstamper]

Here I was, HOPING, to get some sort of direction based on various shooters and hope to see a consensus of an opinion. The laughs on me. There has not been much of a consensus at all. 

I have looked at the travel of my bolt. with the current setup (see above posts for my setup) the bolt is just past the BHO. I was sure it was moving more than that. I will be leaving the system as is for now. I might try a stiffer spring to get the bolt to move faster on the return to battery but there is not much I can do to get the bolt to physically be any closer to the breech face without completely forgoing the BHO mechanism. 

[edwin garcia]

In my short time shooting PCC, I have settled on using Blitz with .308 spring in my JP rifle. At first, it was obvious the felt recoil is more manageable than the silent capture buffer that the rifle came with. However, I noticed the consistency of the recoil impulse varies every so often, some shots felt cycling longer than other. Someone suggested short-stroking the buffer. I added a ~1/4" rubber bump at the other end of the spring opposite the Blitz. The results are more consistent, shot-to-shot, impulse.

 

In the end, I decided to tame the recoil impulse and maintain visual consistency. My advice is to try within reasonable (and safe) means and decided if it's worth the effort. Will it improve your game or will it be just another technical feature in your equipment? Hope this helps.

[MikieM]

I assume by muzzle flip you are referring to recoil?

Recoil is produced by gas pressure in the chamber, when the powder charge is ignited, and continues (in diminishing degrees) as the bullet travels down the barrel.

The only way to mitigate the felt recoil from this action is to either add weight to the gun, or reduce the powder charge, both of which have their limitations.

In another post I alluded to a friend of mine who weighs in at 275 pounds, has legs like tree trunks, and hands like a six inch bench vice, who is practically impervious to recoil. In other words, felt recoil is different for all of us.

 

Keep it simple. Develop a lode that will give you a PF of 130 (128, or 132, is fine). Choose a bolt/buffer combination that is heavy enough to safely allow your gun to function properly. Then find a buffer (recoil) spring that mates up with the above two items (there are several to choose from). Whether you feel that a LRHO device, or even a bolt catch, is necessary is entirely up to you. I myself don't need either, and I know others who feel the same way.

 

Remember. You don't tame recoil, but rather you learn to live with it.

 

 

 

 

 

[Flatland Shooter]

1 hour ago, MikieM said:

I assume by muzzle flip you are referring to recoil?

 

 

I view these as two different animals.

 

My goal is to minimize muzzle movement.  If that requires more recoil, so be it.   I did a bit of experimenting with new loads around Christmas time.  Based on some stuff I had read, increased power factor can lead to less muzzle movement.  

 

I bumped up the powder on my favorite load to achieve a PF in the 145 range and it did tame the dot movement.  At the practice range, the timer indicated faster splits with the same or better accuracy.

 

There is increased recoil but not enough to make me go back to the 132 PF loads.

[MikieM]

I will have to try it myself, but I am dubious, Flats.

Increasing the PF by increasing the powder charge would cause the gun to cycle faster. That would account for the faster splits, obviously. And, true enough, accuracy can sometimes be enhanced by an increase in velocity. Bullets and twist rates come into play here. 

But, if dot movement is relative to recoil, I don't see how increasing recoil with an increase in the PF will reduce dot movement. 

Perhaps the increase in recoil causes you to take a more firm grip in the gun, or perhaps lean into it more. 

Edited February 13, 2018 by MikieM

[Garmil]

the cycle faster = faster splts I don't really understand.  what kind of splits are you guys running? and has outrunning a "slow cycling" gun been an issue?