BSA R10 Accuracy Issues

[Nitrocrushr]

******Update*******On page 3 you will see that this issue has been resolved and the R-10 is shooting GREAT   Feel free to browse through this post to see what led up to the final fix, or jump to page 3 for the final summary

For an even quicker summary, the issues were;

Chrome Plating flaking off of the pellet probe.  Literally hundreds of tiny shavings everywhere, including tiny shavings inside the bore
     Thoroughly scrubbed all loose plating from pellet probe and inner pellet probe port with Scotch Brite
     Completely polished pellet probe with 1200 grit wet/dry - inner layer of plating appears to be adhered ok and no more shavings coming off
     Flushed all shavings from bore, action and magazines (both single shot and 10-shot rotary)

Lead fouling at the end of the choke
     WD40 soaking and bronze brush to remove fouling
     Lapped bore with Clover 400 grit
     Lapped crown with Clover 400 grit and brass crown lap from Brownells


Today I took the R10 outside for some accuracy testing.  The rifle is a BSA R10 MK2 in .22.  I have installed a Huma regulator and always fill to 220 BAR.

I have been from 130-140 BAR on the regulator, running rsterne's hammer spring exercise at each setting and adjusting to a hammer spring tension that is right at the shoulder for whatever setting I am testing.  Velocities have been extremely consistent, with my most recent setting at 139 BAR, hammer spring set right at the shoulder with an average velocity of 897, Extreme Spread of 6 and Standard Deviation of 1 across 32 shots before gradually dropping off of the regulator.  Incredibly consistent rifle with that Huma regulator   It does seem to prefer settings from 135-140 BAR

On target at 50 yards I have tested various combinations of BAR settings and velocities, with several pellet types (JSB 15.89, JSB 18.13 and AA 16 grain)

Looking at the groups, this rifle is acting like my TX200 did when the bore was fouled.  All 3 pellet types will drill a single hole at 30 yards, but then fall apart at 50 yards.  Groups at 50 yards average 3/4" ctc.  I have had 3 or 4 in a 1/4" hole, then a flier 1/2" away.  Some groups are 3/4" with all fliers, no pellets touching.  No pellet change or velocity change has had an impact on this.  I even pulled the scope and installed another scope, no good.  Tested a few groups with the barrel shroud off, no change.  Sand bag position changes, same.  One of the times when it was acting up at 50 yards, I shot a group at 30 yards....it was about 3/4"

I did notice that when I ran dry patches through the bore, it seemed very greasy.  I have been dry patching with my crown saver every 75-100 shots and can feel no lead fouling.  Late this afternoon I ran a couple dry patches through the bore, then used 2 patches lightly dampened with alcohol to try and get the greasiness out, followed by a couple more dry patches.  After this scrub I could definitely feel that the patches had some drag on them and the bore was no longer greasy.  Groups after this were VERY good   The wind was right to left from 2-6 mph and I was getting 5-6 in 1/4-3/8" ctc holes, with only an occasional flier causing the groups to be 1/2" ctc or a bit less, but a HUGE improvement.  I wrote the occasional fliers off to the cross wind.  Aside from that, the rifle seemed exceptionally easy to group single tight holes at 50 yards after this bore scrub.  The alcohol scrub was the only time I made an impact on the groups today, and all 3 pellet types grouped very well during the shot string following this bore cleaning.  The accuracy issues returned soon after the next tank fill.

Looking at these JSB's, I noticed that they have a slippery coating on them.  I think this is what is making the bore greasy.  Are there PCP rifles that simply do not like the slippery, pre-lubed pellets?  Would it be worth a try to soak a tin in hot water and a degreasing dish washing soap?  This is the only thing I can think of at this point.  When bore has a greasy feel to it, groups are radical.  Scrub it with alcohol and the rifle seems to group.

Thoughts?

Steve

[Dairyboy]

I'd clean some and just see. Sounds highly possible that could help alot

[Nitrocrushr]

I'd clean some and just see. Sounds highly possible that could help alot

Thanks Dillon, I'm going to give it a try.  I'll scrub the grease out of the bore and shoot a couple strings of degreased JSB's.  By the end of the 2nd string I'll know if it worked.  Simple enough

By the way, I'm using the single shot tray and not the rotary magazine.

Steve

[TunedAccuracy]

To me it sounds like a wind deflection issue.
The difference between a 2 MPH wind and a 6 mph wind , is profound.
This is not going to rear its ugly head at 30 yards nearly as badly as it will at 50.
At 75 and 100 yards the groupings fall apart completely.

Keep in mind that wind isn't just wind from one direction. It's turbulence. It can shift your point of impact in all directions.
Wind can also affect the projectile many times with various different deflections on its way to the target.
This is why people have a hard time explaining what they are calling fliers.

For instance. A shooter who knows how to dope the wind, does so at 50 yards holding off to the left of Zero to compensate for wind coming from his left side.
Result: the projectile hits right where he was aiming. Whereas the 3 shots prior connected with bullseye.
Additionally the shooter continues to hold left because the majority of his shots are hitting close to, or bullseye. All of a sudden one strays off to the right 1/4 inch.
It happens all the time.

You were probably not holding off for wind and just going for group size. Figuring all projectiles should hit close to each other in a 2-6mph wind.
It will make you scratch your head, but it probably isn't going to happen. At 75 and 100, it gets really bad. Unmercifully bad.
I'm pretty sure there is nothing wrong with the scope you were using and that this is the culprit.

All the symptoms are there.

[Nitrocrushr]

To me it sounds like a wind deflection issue.
The difference between a 2 MPH wind and a 6 mph wind , is profound.
This is not going to rear its ugly head at 30 yards nearly as badly as it will at 50.
At 75 and 100 yards the groupings fall apart completely.

Keep in mind that wind isn't just wind from one direction. It's turbulence. It can shift your point of impact in all directions.
Wind can also affect the projectile many times with various different deflections on its way to the target.
This is why people have a hard time explaining what they are calling fliers.

For instance. A shooter who knows how to dope the wind, does so at 50 yards holding off to the left of Zero to compensate for wind coming from his left side.
Result: the projectile hits right where he was aiming. Whereas the 3 shots prior connected with bullseye.
Additionally the shooter continues to hold left because the majority of his shots are hitting close to, or bullseye. All of a sudden one strays off to the right 1/4 inch.
It happens all the time.

You were probably not holding off for wind and just going for group size. Figuring all projectiles should hit close to each other in a 2-6mph wind.
It will make you scratch your head, but it probably isn't going to happen. At 75 and 100, it gets really bad. Unmercifully bad.
I'm pretty sure there is nothing wrong with the scope you were using and that this is the culprit.

All the symptoms are there.

Thanks Quigley, that is a definite possibility.  I'll have to test again in calmer conditions.  I was shooting due West and wind was north to south.  Perhaps the tight groups I was seeing occurred when the wind was steady.  I was not doping at all.

Steve

[TunedAccuracy]

Thanks Quigley, that is a definite possibility.  I'll have to test again in calmer conditions.  I was shooting due West and wind was north to south.  Perhaps the tight groups I was seeing occurred when the wind was steady.  I was not doping at all.

Steve

You are most welcome, sir.
I have encountered what you are experiencing many times.
I'm fortunate in that, I have my own outdoor range that I can light up at night at 25, 50 , 75 and 100 yards.
Early morning, late evening and night is when winds ( or lack thereof, I should say)  are most optimal for precision air guns.
Many nights give you premium shooting conditions. This is how you can determine true fliers.

[Nitrocrushr]

Thanks Quigley, that is a definite possibility.  I'll have to test again in calmer conditions.  I was shooting due West and wind was north to south.  Perhaps the tight groups I was seeing occurred when the wind was steady.  I was not doping at all.

Steve

You are most welcome, sir.
I have encountered what you are experiencing many times.
I'm fortunate in that, I have my own outdoor range that I can light up at night at 25, 50 , 75 and 100 yards.
Early morning, late evening and night is when winds ( or lack thereof, I should say)  are most optimal for precision air guns.
Many nights give you premium shooting conditions. This is how you can determine true fliers.

I bought a portable flood light Quigly, so now I can test at night when the wind is lowest (hopefully dead calm)   I took a look at approximate velocities and BC's at 50 yards, and then entered cross breeze varying from 3-6.  No doubt, this would have been the variation I was seeing.  I should have known better as my springers are sub 12 fpe and I always pick calm when I want to group test.  For some reason I was thinking that the FAC .22 would resist the wind drift a little better in the light breeze.  Being a 100% direct cross breeze didn't help either .  I should have known better. There are tools available and I didn't use them

Looking forward to follow up testing in calm conditions. After I see that it groups at 50 and beyond I'll pick the pellet it likes best, and I can then begin shooting in the breeze and practice doping

Steve

[Tweeter]

Steve, if you can get that flood light looking at the skirt of the pellets as you shoot you should be able to easily see if they're spiraling on you.  At first I thought you may have an issue with the muzzle crown (I had a bad crown on a .177 scorpion that made every pellet spiral) but where your problem comes and goes I doubt it's that.  Good luck to you sir, I hope you get it sorted!

[solder]

Lots of variables can cause a loss in accuracy. I just went through a period with my BSA R10 MK2 .177. It would be nice to be able to "accurately" identify the cause at each juncture but I'm just not that competent. When you finally get it sorted and accuracy returns, that sigh of relief is welcome...until the next time. Longer distances make things more difficult but it's still fun to push limits and learn.

[Nitrocrushr]

I did some more shooting tonight and I think I made some headway in narrowing down the root cause.  I will outline the steps of my testing in order with photos below.

Instead of 50 yards I decided to do all my tests tonight at 30 yards.  I knew the BSA R10 could print single hole at this distance, but towards the end yesterday, it was scattering even at 30 yards, and pretty badly too.

First group with R10 at 30 yards, rifle was untouched since yesterday.  Looks like a shotgun blast.  I was aiming for the "0" on the target



As a test for myself, I grabbed my Air Arms Pro-Sport .177 (11.8 fpe).  Here is a 5-shot group at 30 yards with that rifle.  A single tiny hole and that is a .177 pellet beside the hole as a reference.  So, this told me there was definitely something going on with this BSA.  Same distance, same conditions, BIG difference.



Took the R10 back to the shop, removed the shroud and inspected the inside of the bore and crown area with a flashlight and a magnifying glass.  I swear it looked like the last quarter inch of the bore had the rifling filled in almost smooth with lead?  Right in the barrel choke area.  I took a .177 bronze brush and carefully inserted it into the bore, and then with light pressure pulled it back out.  I repeated this all the way around the end of the bore until it looked like the rifling was clean.  Next, using my crown saver I pulled 2 dry patches through the bore.  Next, 2 patches dampened with alcohol to remove the lube from the JSB pellets.  Lastly, 2 more dry patches.

Next, I put some alcohol into a plastic container and sloshed 15 pellets around to remove all of the JSB lube.  I then dumped them out onto a towel and thoroughly dried them.

Reinstalled the barrel shroud and back to the range.  Using my single shot adapter I began shooting a group.  All pellets were going into the exact same hole at first.  At about shot 5, the hole began to grow.  It was even, but getting larger........and then on shot 9 the POI shifted suddenly to about 1/2" high.  Here is that group.



I then moved over to another area of the target and shot the remaining 6 shots.  I was aiming at the cross point of the lines below the #2 on this target.  Look how they were beginning to scatter in less then 10 shots.  Again, this was all on the same target, 30 yards and exact same conditions.




This testing told me that the JSB lube had nothing to do with it, and I am guessing I have a fouling problem in this barrel right inside the bore in the area of the choke.

Yesterday after the barrel clean, I had a 1/4" 5 shot group at 50 yards, then it was all down hill after that.  This matches what I saw tonight at 30.

Thoughts?

Steve

[TunedAccuracy]

Hmmm.
Single load a pellet and Put a Kleenex over the top of the pellet port.
Fire the shot and watch the kleenex. If you see a puff or air hit it , you have a defective breech o-ring. Or if it sounds funny when firing.
This combined with wind.....well.
Worth a try.

[Nitrocrushr]

Hmmm.
Single load a pellet and Put a Kleenex over the top of the pellet port.
Fire the shot and watch the kleenex. If you see a puff or air hit it , you have a defective breech o-ring. Or if it sounds funny when firing.
This combined with wind.....well.
Worth a try.

Gave it a try, no leak detected.  It's still very consistent over the chronograph to.  Single digit ES.

Steve

[SpiralGroove]

I did some more shooting tonight and I think I made some headway in narrowing down the root cause.  I will outline the steps of my testing in order with photos below.

This testing told me that the JSB lube had nothing to do with it, and I am guessing I have a fouling problem in this barrel right inside the bore in the area of the choke.

Yesterday after the barrel clean, I had a 1/4" 5 shot group at 50 yards, then it was all down hill after that.  This matches what I saw tonight at 30.

Thoughts?  Steve

Hey Steve,
Was going to mention this last night, but I thought this discussion was a little out of my "Area".
However, it seems pretty clear the barrel's choke is overly (choked) Tight .
Trying to remember how the pull the barrel, so that you can clean using a jag from the breach.  Once this is accomplished, I think you need to lap the bore with some lapping paste, especially the choke area.

Then run a pellet down the barrel for to ensure consistency of movement, with some tightening in the choke area. 

Contact Motorhead and see what he thinks, but everything else, as far as air flow, is running perfectly. 
Gotta be the barrel .  This problem is Scott's forte .

Good luck .

[Nitrocrushr]

I did some more shooting tonight and I think I made some headway in narrowing down the root cause.  I will outline the steps of my testing in order with photos below.

This testing told me that the JSB lube had nothing to do with it, and I am guessing I have a fouling problem in this barrel right inside the bore in the area of the choke.

Yesterday after the barrel clean, I had a 1/4" 5 shot group at 50 yards, then it was all down hill after that.  This matches what I saw tonight at 30.

Thoughts?  Steve

Hey Steve,
Was going to mention this last night, but I thought this discussion was a little out of my "Area".
However, it seems pretty clear the barrel's choke is overly (choked) Tight .
Trying to remember how the pull the barrel, so that you can clean using a jag from the breach.  Once this is accomplished, I think you need to lap the bore with some lapping paste, especially the choke area.

Then run a pellet down the barrel for to ensure consistency of movement, with some tightening in the choke area. 

Contact Motorhead and see what he thinks, but everything else, as far as air flow, is running perfectly. 
Gotta be the barrel .  This problem is Scott's forte .

Good luck .

Hi Kirk, When I first got the rifle I stripped it down, removed the barrel and fully polished the bore with VFG felt pellets soaked in oil and smothered with JB Bore Paste.  I have done this on all my rifles so far.  When I was done I slowly pressed a pellet through the bore and the bore was very smooth, with what felt like only a slight choke at the very end.  I would say it is no tighter than any of the chokes on my Air Arms or Weihrauch springers.  It didn't feel bad at all.  Like I said in my post above, I am almost certain what I was seeing was the rifling almost smoothed over completely in the last 1/4" in the choke area.  I used a flashlight and a big magnifying glass and it sure looked smooth to me. 

Immediately after scrubbing the choke out and cleaning the bore, the rifle was single hole again at 30 yards.  But as I said above, this is short lived and it begins to scatter again in less than 10 shots.

I could pull this barrel off again and concentrate on polishing more in the choke area, but if the barrel is off....I'm more inclined to just replace it.  Before the fouling hits, this thing will dump 5 in a 1/4" at 50 yards so it would be worth it to me to get that accuracy without the fouling

You're right, this is one of Scott's areas.  Hopefully he will chime in here before too long


Steve

[SpiralGroove]

Like I said in my post above, I am almost certain what I was seeing was the rifling almost smoothed over completely in the last 1/4" in the choke area.  I used a flashlight and a big magnifying glass and it sure looked smooth to me. 

Immediately after scrubbing the choke out and cleaning the bore, the rifle was single hole again at 30 yards.  But as I said above, this is short lived and it begins to scatter again in less than 10 shots.

I could pull this barrel off again and concentrate on polishing more in the choke area, but if the barrel is off....I'm more inclined to just replace it.  Before the fouling hits, this thing will dump 5 in a 1/4" at 50 yards so it would be worth it to me to get that accuracy without the fouling

You're right, this is one of Scott's areas.  Hopefully he will chime in here before too long
Steve

So Steve,
After bore brushing, was the rifling nice and visible at the choke, or do you think just too much choke, causing lead build up at that point?

Boy, I'd hate to pay for another barrel if the current one can be fixed .  Then again, if purchased from PA or AGD, they may replace it for free!  After all, it's not like you're a newbie, trying "Cowboy methods" to solve the problem .

Good Luck

[Nitrocrushr]

Like I said in my post above, I am almost certain what I was seeing was the rifling almost smoothed over completely in the last 1/4" in the choke area.  I used a flashlight and a big magnifying glass and it sure looked smooth to me. 

Immediately after scrubbing the choke out and cleaning the bore, the rifle was single hole again at 30 yards.  But as I said above, this is short lived and it begins to scatter again in less than 10 shots.

I could pull this barrel off again and concentrate on polishing more in the choke area, but if the barrel is off....I'm more inclined to just replace it.  Before the fouling hits, this thing will dump 5 in a 1/4" at 50 yards so it would be worth it to me to get that accuracy without the fouling

You're right, this is one of Scott's areas.  Hopefully he will chime in here before too long
Steve

So Steve,
After bore brushing, was the rifling nice and visible at the choke, or do you think just too much choke, causing lead build up at that point?

Boy, I'd hate to pay for another barrel if the current one can be fixed .  Then again, if purchased from PA or AGD, they may replace it for free!  After all, it's not like you're a newbie, trying "Cowboy methods" to solve the problem .

Good Luck

I could start to see the rifling definition again, but I think it still had some fouling.  Thats why it only lasted for less than 10 shots.  The choke didnt feel all that tight, perhaps there is some roughness within the choke that is holding lead? I did see some faint lines at the end when the barrel was new.

Steve

[Nitrocrushr]

Throughout all of this, the velocities have been EXTREMELY consistent.  Here is a shot string from yesterday.

Extreme Spread - 6
Standard Deviation - 1
33 regulated shots before gradually coming off the regulator. 

[Nitrocrushr]

I found my pictures showing the inside of my bore.  You can see the faint lines I was talking about.  They were still visible after polishing.  These were taken when barrel was new.

[Motorhead]

400 Clover, Tight patches on a round jag tip/hard rod and give it a good burnishing job.
Too bad your across the country ... barrel in hand a 20- 30 min process

[KnifeMaker]

This may sound crazy, but you didn't mention the way you fill.

Reason I ask, is that some showbox owners using the newer silicone oil lube  system on them is putting silicone oil into the fill bottles or reservoir of the guns. And of course, it will leave a fairly thick film of silicone in the barrel is short order.

This is actually a welcome thing for a big bore shooter. But not for pellet shooting rifles. It's too thick!

Don't know that this is the type of filling you are doing. Just a thought.

Also, looking at the pic's of your crown, it is beautifully recessed. However, I do not see an actual crown on the very edge for the rifling. Odd! 
Knife