.25 green mountain barrel from crosman

[ShakySarge]

Very interesting Scott and Travis. I wonder what is causing the difference in the older ones. I know the one's Travis measured are brand new so I assume the newer stock. What year was your barrel Scott? Perhaps my rod isn't spinning properly. That could produce the drastic differences.

[Motorhead]

Very interesting Scott and Travis. I wonder what is causing the difference in the older ones. I know the one's Travis measured are brand new so I assume the newer stock. What year was your barrel Scott? Perhaps my rod isn't spinning properly. That could produce the drastic differences.

I got this particular GM .25 give or take @ 2 years ago

[ShakySarge]

Gotcha Scott. I have no doubt that it is my rod that isn't spinning as it should. Was just messing with it and it has a couple rough spots when I hand spin it so that likely is the reason for such random numbers. Perhaps I should get a new cleaning set as these are almost 20 years old.......lol.  Have to run out to the store later anyways and will pick up new rods. I imagine I will get the same measurements.

[Motorhead]

Gotcha Scott. I have no doubt that it is my rod that isn't spinning as it should. Was just messing with it and it has a couple rough spots when I hand spin it so that likely is the reason for such random numbers. Perhaps I should get a new cleaning set as these are almost 20 years old.......lol.  Have to run out to the store later anyways and will pick up new rods. I imagine I will get the same measurements.

Just add another patch to increase the friction against jag tip.

[oldpro]

Clean barrel and I use gun oil on cotton swab so it rotates well with rod .

[ShakySarge]

both good points, thanks guys. I hate putting out false information when it's something so easy.

[K.O.]

well I do know from what I have read that say a 1:14 twist button rifled barrel can have variations of twist in the barrel and some variation from barrel to barrel happen...

Lija uses a guide bar that matches the twist rate of the button because they believe the in barrel fluctuation of twist rate can harm accuracy...

but from the old timers and reading the variation would be like 13.8 or 14.2 for a 14 twist barrel if it was one that varied...

can do a search see if I can find corroboration later... but I do believe there is some variation... 

But we(I included) finding this much difference well am dumbfounded... I guess I could be that bad at measuring... and we get what we think we should get... It fooled my eye also if that is the case... because I could see the twist was faster in the Mrod barrel than my xl725 barrel also... same with my .22 Max and Disco barrels... when I look thru them side by side I can visibly see the difference in twist...

Scott do you know what year the barrel is... and would still love to see where you read it is 1:19...

here is a 2013 thread and a member triple checked and got 1:18   

https://www.gatewaytoairguns.org/GTA/index.php?topic=41679.0 

Now every once in a while you need a new button and that can cause variance also but not at the scale we are seeing...

Man I wish the industry respected their customers enough to publish their specs...

CAUSE right now just call me BAFFLED......... ......... ........ are some of us maybe me that bad at using a good TIGHT patch to find twist rate...?

[K.O.]

Very interesting Scott and Travis. I wonder what is causing the difference in the older ones. I know the one's Travis measured are brand new so I assume the newer stock. What year was your barrel Scott? Perhaps my rod isn't spinning properly. That could produce the drastic differences.

Boy a lot of replies while I was typing... basically a loose patch will tend to read slower than twist...

[mackeral5]

I used a tight fitting nylon brush on a tipton ball bearing cleaning rod.  I made a flag with blue tape and watched it to count a full rotation.

[Motorhead]

I used a tight fitting nylon brush on a tipton ball bearing cleaning rod.  I made a flag with blue tape and watched it to count a full rotation.

THAT WORKS !

[triggertreat]

I just checked my two .25 barrels and both are 1:19 RH twist.  Much slower than I was thinking.  Earlier thread (2016) reports were saying 1:15.5. https://www.gatewaytoairguns.org/GTA/index.php?topic=110616.msg1085634;topicseen#msg1085634

[ShakySarge]

Will re-check mine with the new bearing rod and the extra patch later this evening. Now wondering what will come to light from the different year barrels.

[K.O.]

I had an discusion with a bud a few years ago about this very same subject... I told him a brush is not good enough that a tight patch is more accurate...

he was getting 1: 10.5 ish in a .223 barrel that I knew was 1:9... with the tight brush method... with the tight patch method I showed it was 1:9 and then showed him the published twist rate...

that was not a choked barrel... in fact I do not measure from the muzzle if I can avoid it for any barrel... 

not saying you guys are wrong but is not how I was taught... it is very easy to get 15-16-17 in the same barrel with a brush... I did the experiment when young with dads Remmy .22...  also did bigger bores and the speed I pushed would change results... 

for me though the tight patch method is the only one I trust when I check...

[ShakySarge]

2013 barrel measures 1:19 with the bearing rod. Measured it 3x with new patches each time. difference between each measurement was less than 1/8".

[triggertreat]

I used a new and tight fitting foam bore-tip on a Dewey rod with an excellent bearing.  I also checked each barrel a number of times to be sure.  None of them wavered from the 1:19 so I'm pretty sure my measurements are correct.

[ShakySarge]

I used a new and tight fitting foam bore-tip on a Dewey rod with an excellent bearing.  I also checked each barrel a number of times to be sure.  None of them wavered from the 1:19 so I'm pretty sure my measurements are correct.

I would agree. It seems that my old rod was not turning properly, still don't know how it gave a tighter twist reading than a looser though. I imagine that the patches not being tight enough allowed it to spin faster resulting in incorrect measurements. Still wonder what the reading will be on the barrel that groups loosely will be though. We shall see. May have to run a scope down it as he may have some pitting in the barrel as I found quite a bit of rust throughout the breakdown and cleaning process of the gun.

[Pelletjunkie]

The variations in twist that you have seen guys post over the years might not be coming from Crosman. It’s the guy trying to measure his rate of twist in his living room. My TJ barrel is their newest twist rate in .25. They found a rate that was more versatile than a .25 auto twist that guys were using previously. I can understand Crosman making one change from what they originally went with in .25 because of feedback and what projectiles people want to shoot. But not 3 or 4 changes in twist.

[ShakySarge]

The variations in twist that you have seen guys post over the years might not be coming from Crosman. It’s the guy trying to measure his rate of twist in his living room. My TJ barrel is their newest twist rate in .25. They found a rate that was more versatile than a .25 auto twist that guys were using previously. I can understand Crosman making one change from what they originally went with in .25 because of feedback and what projectiles people want to shoot. But not 3 or 4 changes in twist.

I fail to see the difference between someone measuring in their living room and someone in a shop. I do however, see the difference in how they are measured depending on who does the measurements. I don’t believe for a moment that Crosman ever changed the twist rate intentionally and addressed that in an earlier post in the thread. I do know that QC is not the greatest with Crosman. Even with that, Crosman doesn’t produce the .25 barrels. There will inevitably be some differences over the years.

[K.O.]

well guys I swear I was not on anything back when I checked my 2014 syrod in 2014... but the 2016 is looking to be 1:19 both by visual and a slightly to loose patch... can make tighter patch but it will not change it much....

re checked my Trail XL 725 Barrels also just to make sure... got 1:19   

Do not want to pull the 2014 barrel but can bet I got it wrong back then... trying to remember if I did the measurement with a rod or dowel...

but yep looks like 1:19 to me...

guys I have had some concentration probs at times maybe even mini strokes... just a couple months ago now had to have work in my lung... had artery in vein out with direct connection... shunted blood past lung and can let stuff thru strait to brain... so it had to be blocked...has been there al my life but they just found it this year(it and two other avms)... point is it may have been one of the here and there strange disconnects I have been suffering for the last 10 years... it is possible but I do not think so... 

It is just I have been checking twist rate since I was a kid cause barrels and their differences always fascinated me... just do not know how I could get it that wrong... I checked a lot of barrels over the years to teach myself about how tight of a patch was needed...

and most of the time if I was getting a off reading it was to the slow side not the fast..?    Jeeze I hate to have to be doubting myself...almost enough to make me stop posting... cause I tend to get frustrated by incorrect info being passed and here I was doing it myself while being very sure I was not passing bad info...

[ShakySarge]

well guys I swear I was not on anything back when I checked my 2014 syrod in 2014... but the 2016 is looking to be 1:19 both by visual and a slightly to loose patch... can make tighter patch but it will not change it much....

re checked my Trail XL 725 Barrels also just to make sure... got 1:19   

Do not want to pull the 2014 barrel but can bet I got it wrong back then... trying to remember if I did the measurement with a rod or dowel...

but yep looks like 1:19 to me...

guys I have had some concentration probs at times maybe even mini strokes... just a couple months ago now had to have work in my lung... had artery in vein out with direct connection... shunted blood past lung and can let stuff thru strait to brain... so it had to be blocked...has been there al my life but they just found it this year(it and two other avms)... point is it may have been one of the here and there strange disconnects I have been suffering for the last 10 years... it is possible but I do not think so... 

It is just I have been checking twist rate since I was a kid cause barrels and their differences always fascinated me... just do not know how I could get it that wrong... I checked a lot of barrels over the years to teach myself about how tight of a patch was needed...

and most of the time if I was getting a off reading it was to the slow side not the fast..?    Jeeze I hate to have to be doubting myself...almost enough to make me stop posting... cause I tend to get frustrated by incorrect info being passed and here I was doing it myself while being very sure I was not passing bad info...

It's all good. I got completely different measurements myself initially. It happens. No big deal. I will still pull the other barrels and check them all as well as the ones that will be here in the next couple weeks. The more we get measurements on, the better as it will identify any minor differences over time.