BSA R10 Mrk II help?

[0akhonor]

One year old Mk II in .177 blows air past the bolt, into the shooters face. Been doing so since new. The majority of the rifles sound is coming from the rear of the rifle as well. Velocity is consistent, accuracy is perfect. Just a shame to have to wear safety glasses for every shot. 10 grain pellets are averaging 900 fps....

Take a look...

 

[HauntedMyst]

You probably just need to replace the o-ring on the pellet probe. There are lots of how to videos on you tube. I'd also guess, based on the video that the ball bearing that holds the probe in place is off. It's possible they forgot to put the spring in place when it was new.

 

[jobrako]

Hey I recently had the same problem,

Part of the bolt is curently pressing against the stock, this causes the chamber to be only partually closed.

To fixt this you need too looses the screw on the bolt and move it a bit upwards.

This should fixt the problem.

The video shows how the bolt moves backwards when you fire.

So when the bolt is closed it shoudn't touch the stock, this way you ensure it's completely closed. 

 

[0akhonor]

Great insite! I also found this-
http://bsaog.co.uk/forum/index.php?topic=56436.30

This is the number two thread on the BSA forum and it was a lengthy discussion on the bolt problem. I've posted the link here, in case anyone searches the thread in the future.

Summary is, there is a custom aftermarket bolt sold overseas made from stainless, with a deeper socket for the ball detent that is supposed to correct the problem. England has the problem even with their 12 ft/lb rifles. Our FAC's really push the envelope. I've asked the vendor if he'll ship to the US and if not, if there is a US source for the improved part. Once I've that info, I'll make one more entry....

 

[jobrako]

The bolt must just turn more when it locks so it can not go back.

 

[HauntedMyst]

I think jobrako nailed it.

 

[jobrako]

These are the up and down positions of the bolt of my gun, as you can see there is a clear gap present in the down position. This ensures that the bolt can make the whole movement to lock the chamber and doesn't come back up when you shoot. The screw in the middle you can easily adjust. It took me just 30 seconds to fix the problem.