BSA R10 Accuracy Issues

[Motorhead]

See  you now have 1st hand experience taking apart the BSA receiver ... Fun huh

[robertr]

 Supposedly it is nickel plating that is coming off, caused by the ball the rides on the bolt.
 There is a member on BSA forum ( Rancidtom ) that makes a Stainless Steel Probe to replace the stock one. Only problem is they are not available yet.
 Keep checking XTX's website as they will be carrying them. I need to get one for my rifle.
 Hopefully that is what is causing your problem, as long as the nickel plating does not scratch your barrel which was mentioned could happen.
Hear is a link to the thread. http://bsaog.co.uk/forum/index.php?topic=56436.0

[Nitrocrushr]

See  you now have 1st hand experience taking apart the BSA receiver ... Fun huh

Oh yeah, loads of fun just to get the barrel off   Oh well, Gave me a chance to look things over real well.  Everything is back together, putting the scope back on now and will be running a through through it just to make sure there are no leaks.  Winds are gusting to 20 mph now so I won't be able to do any target testing until tonight or tomorrow morning.  The bolt is smooth as glass and all remaining coating seems solid.  I gave it a thorough scotch brite scrubbing followed by 1200 grit wet/dry.  I covered everything on that probe including inside the port and all edges.  Super smooth now, time will tell.

The bore turned out well.  All lead fouling is gone

[Nitrocrushr]

Supposedly it is nickel plating that is coming off, caused by the ball the rides on the bolt.
 There is a member on BSA forum ( Rancidtom ) that makes a Stainless Steel Probe to replace the stock one. Only problem is they are not available yet.
 Keep checking XTX's website as they will be carrying them. I need to get one for my rifle.
 Hopefully that is what is causing your problem, as long as the nickel plating does not scratch your barrel which was mentioned could happen.
Hear is a link to the thread. http://bsaog.co.uk/forum/index.php?topic=56436.0

Thanks!  Hopefully this will take care of the problem.........but, if this doesn't work and the probe starts to flake again, I will keep an eye out for the stainless probe   The bore looked good, but I wouldn't want to shoot thousands of rounds with the metal flakes blowing into the bore   Makes me wonder how many folks are dealing with this but aren't aware of the problem.

Steve

[Nitrocrushr]

The R10 is all done, everything back together.  The wind picked up too much to test outdoors so I ran some shots through the chronograph inside.  I left the Huma regulator set for 139 BAR, but backed off on the hammer spring 2 full turns from the factory setting.  I was able to stay on the knee of the curve and velocity is now at about 865 fps with JSB 15.89 (26.65 fpe).   JSB 18 grain are coming out at 826 fps.  Still getting single digit ES and no leaks.  Bolt is VERY smooth

While my indoor target is only 13 yards, I still wanted to check things after the bore work.  All shots went into a single hole, that's a good sign.  No sign of chrome flaking, and after I got done shooting and inspection of the bore showed no fouling, rifling looks great   Hoping tomorrow morning will be calm so I can get back outside.  I feel really good about the results so far...but you know how that is....outdoors at distance will tell the tale


One tiny hole at 13-yards......that's a good sign




Bore and rifling look great, no sign of fouling




Decided to install the Pinkney Engineering polished aluminum safety button  while it was apart.  Little longer than the stock button, I like it



Steve

[robertr]

 Looks good, did you use your mag at all? If you did you could also disassemble and clean it out to, I have noticed flakes can get in the mag as well. The safety knob is cool.

[Nitrocrushr]

Looks good, did you use your mag at all? If you did you could also disassemble and clean it out to, I have noticed flakes can get in the mag as well. The safety knob is cool.

Thanks I didn't use the magazine today, but I did use it last week for chronograph testing.  Good idea on stripping it down and cleaning any chrome flakes out.  I'm sure there's some in it.  I'll do that tomorrow.

Steve

[Nitrocrushr]

Well I wasn't able to beat the wind this morning, but I shot some groups anyway.  From what I can tell the issue has been resolved at this point.  The rifle is shooting MUCH better, and is printing tight groups with ease

Here are a couple back to back groups shot at 50 yards;


My rinky dink little wind flag this morning   After seeing the affects on the group, I tried to shoot when it was stretched out like this




First 50 yard group was with the JSB 15.89 grain.  Wind flag was stretched out from right to left causing the groups to be about 1/2" or so to the left of my vertical aim point.  On shot #2, the flag dropped and my POI was right on with vertical aim point.  I shot 4 more shots, but made sure the flag was stretched out for each remaining shot, end result was 5 of the 6 shots going into a core group that was sub 1/4" ctc.





Next 50 yard group was shot with the Air Arms 16 Grain.  I shot all 5 while the flag was stretched out, all went into the core group just left of my vertical aiming point.





Forgot to mention yesterday that in addition to the Clover 400 bore lapping, I also lapped the crown with a brass tool from Brownells.  Low speed on cordless drill, moving drill in a rotating movement with even pressure about 30-45 seconds, then reversed drill and repeated for another 30-45 seconds.   Clover 400 was used for this.  The factory crown was recessed, but squared off.  No taper.  Also touched up the breech end of the barrel.



I finished up with a shot string to test out my latest settings.  139 BAR with hammer spring backed off 2 full turns from factory setting.  For the first time I was able to see the effects of a light hammer strike after the rifle came off the regulator at shot #42.  Shots 1 - 42 resulted in 852 fps average and an Extreme Spread of only 11 fps.

Looking at the velocities, it would seem as if the rifle would be very shootable for almost 60 shots.  Not sure at which point POI would begin to change enough making it not shootable?  From shot 43 through 56 the ES was still below 20 fps.

At this setting I am at about 94-95% of max velocity at 139 BAR.  Might crank it in another half turn, maybe. 




Thanks to everyone for their input on this issue, I really appreciate the help I received Starting out I had no idea what was causing the accuracy problems and the ideas generate here helped me to plug away at things until it was finally resolved

Motorhead - Thanks for your help behind the scenes with the bore lapping process

Keeping my fingers crossed now, hoping that the bolt probe plating will no longer flake off.  I am still planning on getting one of the stainless probes when available.

With about 140 shots through the rifle since the tear down yesterday the bore still looks GREAT and bolt is silky smooth!!!  At about 70 shots I ran 3 dry patches through the bore, no fouling.  Crown still looks great with no build up

Here is a picture of the bore after 140 shots.  Not even a hint of fouling



Steve

[Dairyboy]

Glad this turned out great! Heck I wish I could shoot that good not in wind lol

[robertr]

  Great job on your R-10, those 1/4 " groups look nice. I have flags like that, coat hanger and ribbon.

[solder]

Great job! I thoroughly enjoyed  this journey and I hope your accuracy issues are resolved.

[SpiralGroove]

Hey Steve,
Excellent Work .

[Nitrocrushr]

Thanks guys This reminds me of the many journeys I took while learning to tune springers.  Most of my learning takes place in the midst of problems, so in a roundabout way this was a good thing

Steve

[DrPutz]

Nice shooting! Those are awesome groups in the wind. 1/2 MOA? That is truly remarkable. I will have to pass this thread on to the person that bought my R10.

Now I am interested in trying to lap my crosman barrel - even if it turns out half as good as yours, I will be a happy camper.

Dan

[Gear_Junkie]

I'm glad it all worked out for you, Steve.  Those are some sweet groups for sure! 

[rkr]

Well done, that's what a good BSA barrel can do and what I expect from my guns. Excellent shooting as well.

[sirira]

I'm glad it worked out for you. Great job on the tinkering and troubleshooting!
Eric

[KnifeMaker]

Steve, I am elated that this R-10 is now performing so well! Exactly what I always heard BSA's were capable of.

I was still a little shocked that they seemingly forgot to actually put a crown on the barrel. Not just the recess.

The Brass screw, or Brownell tool both do a very good job!

Now---Happy Shooting!!!
Knifemaker