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3gunnuts

JP jumps on the short stroke bandwagon

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Had a chance to run 2 nearly identical guns side by side (1 port comp on bolt weight removed gun vs 2 port comp on full weight carrier) with 2 different shooters.  .  Both of us saw a NOTICEABLE difference in dot movement and spread when firing fast splits/hammers at 30'.  There was less movement of the dot up and to the right with the weight removed and it also dipped less when the bolt came forward.  Recoil impulse felt more subdued with the weight out.  Target with the smaller groups is the two of us shooting my PCC with the weight removed.  Larger group target is with full weight carrier.  Both guns have the same triggers and optics. Not sure I can get it to shoot any flatter. Maybe adding a wave spring and a quarter at the back but I am pretty happy with the results at this point.

 

 

 

 

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10 hours ago, 3gunnuts said:

Maybe adding a wave spring and a quarter at the back but I am pretty happy with the results at this point.

More great info, and pictorial evidence to back it up.

 

I got my Taccom3 yesterday and threw it in! I had time to get out today and fire about 35rds with 5 or 6 different ammo configurations.

 

It was noticeably different than my 7.5oz Kaw Valley buffer and spring. It was  smoother, maybe not quite as much as I expected though. In fairness, 35rds isn't much and I have a match Sunday, that will tell the story.

 

My first thought after shooting today was to try it with the bolt weight out, the nice post above backs up that theory. The second was to play with my next lot of ammo, I just ordered 4000 115gr RN bullets that should be here early next week. Every round I fired today fed, fired and ejected with no issues, that makes me feel a ton of relief. 115's, 147's, a few different loads of the 115's and 2 rounds loaded with SNS red bullets I picked up after the last match, no clue what they were.

 

My normal 115gr load is loaded with N350,( because I have 2# of it) and published to be 1130fps. They seem snappy, even with the Taccom3, although better than with the old buffer system. I was thinking yesterday I bet they are faster than 1130 with the 16" barrel on my PCC gun. I will chrono those and adjust when I start loading again.

 

A bunch of the rounds I shot today were a 115gr TC shaped bullet, loaded to probably 950-975fps for target practice with my M&P, at least 2 years ago before I had ever heard of a PCC gun. I set up shop today at 35-40 yards, just so I could really tell what this gun is doing. I also usually practice at that distance or a bit less because it makes the matches seem up close and personal ! I have a couple 8" circles, 5 or 6 18"X24" plates, 2 IPSC steel targets and one pepper popper. Those light target rounds had no problem knocking the big popper down at 40yds, so I'm pretty sure I can back down the match ammo a bit ?

 

One question to anyone that can answer......................I knew from watching the videos this buffer system allows you to retract the bolt pretty effortlessly until you hit that wall. I was surprised at first how stiff it got as you went back. My normal protocol on any loaded start was to lock the bolt back, put the mag in and close the bolt. I am thinking that may not be the best way with this set up ? The bolt has a ton of tension on it and while holding the charge handle, you can feel it in the bolt release.

 

Another match this Sunday, real world report on the Taccom3 to follow.

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36 minutes ago, SJMPCC022 said:

More great info, and pictorial evidence to back it up.

 

I got my Taccom3 yesterday and threw it in! I had time to get out today and fire about 35rds with 5 or 6 different ammo configurations.

 

It was noticeably different than my 7.5oz Kaw Valley buffer and spring. It was  smoother, maybe not quite as much as I expected though. In fairness, 35rds isn't much and I have a match Sunday, that will tell the story.

 

My first thought after shooting today was to try it with the bolt weight out, the nice post above backs up that theory. The second was to play with my next lot of ammo, I just ordered 4000 115gr RN bullets that should be here early next week. Every round I fired today fed, fired and ejected with no issues, that makes me feel a ton of relief. 115's, 147's, a few different loads of the 115's and 2 rounds loaded with SNS red bullets I picked up after the last match, no clue what they were.

 

My normal 115gr load is loaded with N350,( because I have 2# of it) and published to be 1130fps. They seem snappy, even with the Taccom3, although better than with the old buffer system. I was thinking yesterday I bet they are faster than 1130 with the 16" barrel on my PCC gun. I will chrono those and adjust when I start loading again.

 

A bunch of the rounds I shot today were a 115gr TC shaped bullet, loaded to probably 950-975fps for target practice with my M&P, at least 2 years ago before I had ever heard of a PCC gun. I set up shop today at 35-40 yards, just so I could really tell what this gun is doing. I also usually practice at that distance or a bit less because it makes the matches seem up close and personal ! I have a couple 8" circles, 5 or 6 18"X24" plates, 2 IPSC steel targets and one pepper popper. Those light target rounds had no problem knocking the big popper down at 40yds, so I'm pretty sure I can back down the match ammo a bit ?

 

One question to anyone that can answer......................I knew from watching the videos this buffer system allows you to retract the bolt pretty effortlessly until you hit that wall. I was surprised at first how stiff it got as you went back. My normal protocol on any loaded start was to lock the bolt back, put the mag in and close the bolt. I am thinking that may not be the best way with this set up ? The bolt has a ton of tension on it and while holding the charge handle, you can feel it in the bolt release.

 

Another match this Sunday, real world report on the Taccom3 to follow.

My bolt does not go back far enough to lock open. I don't really care as I just stuff a mag in and cycle. I use a 57 round mag downloaded to around 50 rods. Have not had any issues.

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13 minutes ago, 3gunnuts said:

My bolt does not go back far enough to lock open. I don't really care as I just stuff a mag in and cycle. I use a 57 round mag downloaded to around 50 rods. Have not had any issues.

Funny you mention that, I got an MBX Mini for the match last Sunday. I have been having problems on unloaded starts and that sure fixed it ! A 47 rd mag loaded with 36 or 37 slides in real easy and feeds no problem !

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@3gunnuts  what bcg are you using and how much does your weight weigh?

 

I have a tool craft bcg - i removed the weight to test - weight weighs 77 grams = 2.75 ounces 

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6 hours ago, Fo0 said:

@3gunnuts  what bcg are you using and how much does your weight weigh?

 

I have a tool craft bcg - i removed the weight to test - weight weighs 77 grams = 2.75 ounces 

 

Possibly stupid question, but why not just use a lighter buffer instead of removing the weight in the BCG?

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I knew from watching the videos this buffer system allows you to retract the bolt pretty effortlessly until you hit that wall. I was surprised at first how stiff it got as you went back. 

 

I haven't seen the video, but isn't this the opposite of what you'd want in a blowback system? Buffer weight and spring tension should keep the bolt closed longer, but MORE tension at the rear of the stroke seems like you're just setting up for a SLAM on closing and/or bolt bounce?

 

I specifically went with the Tubb's 308 spring for this next build b/c it has MORE tension on the bolt closed and LESS when open. Not saying one is right or wrong, just curious. 

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2 hours ago, Acer2428 said:

 

I haven't seen the video, but isn't this the opposite of what you'd want in a blowback system? Buffer weight and spring tension should keep the bolt closed longer, but MORE tension at the rear of the stroke seems like you're just setting up for a SLAM on closing and/or bolt bounce?

 

I specifically went with the Tubb's 308 spring for this next build b/c it has MORE tension on the bolt closed and LESS when open. Not saying one is right or wrong, just curious. 

I'm going to try it with the weight out of the bcg today.

 

What u say makes sense but I assume they design it that way for a reason ?

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2 hours ago, STIboy said:

 

Possibly stupid question, but why not just use a lighter buffer instead of removing the weight in the BCG?

 

I am using an MBX buffer short stroked 

 

2 hours ago, Acer2428 said:

 

I haven't seen the video, but isn't this the opposite of what you'd want in a blowback system? Buffer weight and spring tension should keep the bolt closed longer, but MORE tension at the rear of the stroke seems like you're just setting up for a SLAM on closing and/or bolt bounce?

 

I specifically went with the Tubb's 308 spring for this next build b/c it has MORE tension on the bolt closed and LESS when open. Not saying one is right or wrong, just curious. 

 

stiffer as it goes back slows down the bolt/buffer during the cycling resulting in a reduction with felt recoil

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What is the theory of removing the weight? It seems the heavier bolt would be slower to result in less felt recoil - unless removing the weight means less mass moving back and forth making up for the faster speed

Edited by Fo0

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4 hours ago, STIboy said:

 

Possibly stupid question, but why not just use a lighter buffer instead of removing the weight in the BCG?

Less reciprocating mass/ inertia and I have the the Taccom set up so I cannot remove weight.

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10 hours ago, Fo0 said:

@3gunnuts  what bcg are you using and how much does your weight weigh?

 

I have a tool craft bcg - i removed the weight to test - weight weighs 77 grams = 2.75 ounces 

I ordered a PSA upper that was supposed to come with their Hybrid bolt but it came with a Faxom style bolt without the logo.  

Bolt weighs 12 1/8 oz

weight weighs 2 1/2 oz  

total weight 14 5/8 oz

 

Original Taccom 3 stage 7 1/8 oz

Taccom with short-stroke upgrade 6 1/2 oz

Spring 2 1/4 oz

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1 hour ago, Fo0 said:

What is the theory of removing the weight? It seems the heavier bolt would be slower to result in less felt recoil - unless removing the weight means less mass moving back and forth making up for the faster speed

The speed will increase slightly as there is less mass to push but it is also less momentum for the spring to absorb.  You can achieve similar results using heavy springs and heavy buffers as well.  It is all about minimizing dot movement.  The test my teammate and I did proved to us which system works better.  Going out now to test with 3 different factory loads and see what works best.  Will update in a bit.

 

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16 hours ago, SJMPCC022 said:

...and 2 rounds loaded with SNS red bullets I picked up after the last match, no clue what they were.

 

First, I strongly recommend you never shoot reloads you pick up off the range unless you know and trust the person who loaded them (maybe not even then).  Some people shoot 9mm Major, and some people may not know what they are doing.  Best not to shoot random range fodder for your safety and that of your gun.

 

16 hours ago, SJMPCC022 said:

My normal 115gr load is loaded with N350,( because I have 2# of it) and published to be 1130fps. They seem snappy, even with the Taccom3, although better than with the old buffer system. I was thinking yesterday I bet they are faster than 1130 with the 16" barrel on my PCC gun. I will chrono those and adjust when I start loading again.

 

I get an additional ~130-140 fps out of my 16" PCC barrel than from my 5" Production barrel with the exact same load.  YMMV, depending on your pistol and carbine barrels.

 

16 hours ago, SJMPCC022 said:

A bunch of the rounds I shot today were a 115gr TC shaped bullet, loaded to probably 950-975fps for target practice with my M&P, at least 2 years ago before I had ever heard of a PCC gun. I set up shop today at 35-40 yards, just so I could really tell what this gun is doing. I also usually practice at that distance or a bit less because it makes the matches seem up close and personal ! I have a couple 8" circles, 5 or 6 18"X24" plates, 2 IPSC steel targets and one pepper popper. Those light target rounds had no problem knocking the big popper down at 40yds, so I'm pretty sure I can back down the match ammo a bit ?

 

A 115gr bullet has to be doing at least 1087 fps to make Minor, otherwise you are shooting for no score.    The load you describe would be sub-minor in your M&P, but might be fine in your PCC.  I would chrono the load out of your PCC before you decide to back it down.  Steel should be set to fall for sub-minor loads, so I wouldn't use that as proof you're at least 125PF.

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Ok so tested at 30ft shooting hammers with 3 different factory loads.  I don't reload pistol so i wanted to see what worked best for factory ammo and figured a lot of guys could use this info. Here is how I felt they ranked in  terms of felt recoil and dot movement. Flinched at least once on each target as I am shooting indoors and guns are louder in the stalls.

 

1) Federal Syntech 150gr Action Pistol Shot the softest with fast dot recovery.

 

2) Federal 124 gr Suppressor Load- Just slightly more movement than the top load but still extremely soft and easy to recover the dot.   I use this in my DVC 3Gun and is my preferred load.  I have not found anything that shoots softer in a handgun and I have tested almost every load from every major manufacturer.

 

3) Remington 115 gr FMJ (mislabeled on the target as FED 115gr) snappier as this is a full power 9mm load. Little bit more violent movement of the dot but still easily manageable. I attribute the tighter group here to clamping down really hard after the first couple shots.

 

 

 

 

 

 

 

 
 
 
No automatic alt text available.
 
 

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13 minutes ago, JAFO said:

 

First, I strongly recommend you never shoot reloads you pick up off the range unless you know and trust the person who loaded them (maybe not even then).  Some people shoot 9mm Major, and some people may not know what they are doing.  Best not to shoot random range fodder for your safety and that of your gun.

 

 

I get an additional ~130-140 fps out of my 16" PCC barrel than from my 5" Production barrel with the exact same load.  YMMV, depending on your pistol and carbine barrels.

 

 

A 115gr bullet has to be doing at least 1087 fps to make Minor, otherwise you are shooting for no score.    The load you describe would be sub-minor in your M&P, but might be fine in your PCC.  I would chrono the load out of your PCC before you decide to back it down.  Steel should be set to fall for sub-minor loads, so I wouldn't use that as proof you're at least 125PF.

You win for best Screen Name.

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On 8/11/2018 at 9:21 AM, STIboy said:

 

I've got the upgrade kit coming in next week.  I'll report back when I have a chance to test it.

I have the upgrade kit in hand, and will test it next week.

 

Also had the JP short stroke version of their SCS come in, and took it to the range today.  Compared it against the newest version of the SCS on the GMR-13.  Result - the heavier buffer (5 titanium weights) with a shorter stroke seemed smoother than the original (3 titanium weights and one steel) with the longer stroke.  Not a night and day difference, but a noticeable one.  Will keep the short stroke version in the gun, and will run it in about a week and a half at the next USPSA match.

 

Load was a 115 gr. bullet over 4.3 gr. of N320.  Haven't chronoed the load yet, but will next week.

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Anyone know the buffer oal of the JP short stroke and Taccom short stroke to compare? 

 

MBX short stroke is 4 and 7/8 "

 

 

 

 

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35 minutes ago, Fo0 said:

Anyone know the buffer oal of the JP short stroke and Taccom short stroke to compare? 

 

MBX short stroke is 4 and 7/8 "

 

Taccom Short Stroke -   4 and 9/16 at rest     4 and 1/8 compressed fully

 

 

 

 

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MBX is only 3 and 1/2" fully compressed - probably to allow LRBHO

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2 hours ago, JAFO said:

First, I strongly recommend you never shoot reloads you pick up off the range unless you know and trust the person who loaded them (maybe not even then).  Some people shoot 9mm Major, and some people may not know what they are doing.  Best not to shoot random range fodder for your safety and that of your gun.

They were left by guys on my squad shooting production, all good. But your point is correct.

 

2 hours ago, JAFO said:

A 115gr bullet has to be doing at least 1087 fps to make Minor, otherwise you are shooting for no score.    The load you describe would be sub-minor in your M&P, but might be fine in your PCC.  I would chrono the load out of your PCC before you decide to back it down.  Steel should be set to fall for sub-minor loads, so I wouldn't use that as proof you're at least 125PF.

I get that, this ammo was loaded for lazy paper punching with my M&P. My point was as slow as it is, it cycled my PCC with the new Taccom3 buffer and knocked a popper down at 40yds, it was never intended as match ammo.

 

3 hours ago, 3gunnuts said:

Less reciprocating mass/ inertia and I have the the Taccom set up so I cannot remove weight.

I just finished my test firing with the bolt weight removed with my new Taccom buffer system. Your post puzzles me so please elaborate.

 

There was a tremendous difference between shooting yesterday with the bolt weight in and today with the weight out. Yowza was it easy to shoot ! Double taps on an IPSC steel target at 35-40yds was effortless. As before, I used three different lots of ammo with two different bullet weights, one being Blaser Brass. That one was actually a bit softer than my 115gr load which surprised me. As I said earlier, I suspect the 1120fps published would be about that in my M&P, more than likely much more in the PCC. Chrono tomorrow will verify. Match day Sunday, we will see what happens. When I reload again I will tweak the loads down a bit with the chronograph. 1100fps out of the PCC should fill the bill quite nicely !

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4 minutes ago, SJMPCC022 said:

They were left by guys on my squad shooting production, all good. But your point is correct.

 

I get that, this ammo was loaded for lazy paper punching with my M&P. My point was as slow as it is, it cycled my PCC with the new Taccom3 buffer and knocked a popper down at 40yds, it was never intended as match ammo.

 

I just finished my test firing with the bolt weight removed with my new Taccom buffer system. Your post puzzles me so please elaborate.

 

There was a tremendous difference between shooting yesterday with the bolt weight in and today with the weight out. Yowza was it easy to shoot ! Double taps on an IPSC steel target at 35-40yds was effortless. As before, I used three different lots of ammo with two different bullet weights, one being Blaser Brass. That one was actually a bit softer than my 115gr load which surprised me. As I said earlier, I suspect the 1120fps published would be about that in my M&P, more than likely much more in the PCC. Chrono tomorrow will verify. Match day Sunday, we will see what happens. When I reload again I will tweak the loads down a bit with the chronograph. 1100fps out of the PCC should fill the bill quite nicely !

I was referring to not being able to adjust the weight of the buffer system.

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7 hours ago, 3gunnuts said:

I was referring to not being able to adjust the weight of the buffer system.

Got it. The only reason I asked was I first bought an Armaspec buffer, which had to have the bolt weight removed to function.

 

I sent it back unfired and bought the Taccom3 buffer. I tried it with the weight in and the weight out of the bolt. It was much better with the weight out of the bolt.

 

Give it a shot. 

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2 hours ago, SJMPCC022 said:

Got it. The only reason I asked was I first bought an Armaspec buffer, which had to have the bolt weight removed to function.

 

I sent it back unfired and bought the Taccom3 buffer. I tried it with the weight in and the weight out of the bolt. It was much better with the weight out of the bolt.

 

Give it a shot. 

 

Hmmm.  Something else to try...

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6 hours ago, STIboy said:

 

Hmmm.  Something else to try...

Yep, have to stay on top of this s**t !

 

Heading out in a bit to chrono my loads and see if I am correct in thinking they are way faster than need be due to the barrel length of the PCC. I will check the M&P also for comparison.

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