Dad's BSA 303 no1 Mk3 groups but point of impact moves between range sessions

[Doekster]

So I got to my Dad's place this weekend and found that he took appart the 303 to see what is going on inside the stock, becuase one of his friends told him that maybe some of the bedding came loose...

Looking at the stock and bedding it all seems to be in order, but when I took the barrel ring and slide it over the barrel, it stopped about 5-8mm behind the point where is should stop. (barrel tappers to the back)

I have done some reading on this barrel rings, and found that the main purpose of this ring is to pull the barrel downwards. So this got me thinking. If this ring should pull the barrel down and the ring can slide deeper onto the barrel than it really should, then I cannot see how it can be pulling the barrel down constantly? Surely there must be a movement here where it should not?

May this be the issue?

[jdpretorius]

That barrel ring might be some thing to try and get rid of. I battled for a long time with mine (same make and model as yours, fitted with synthetic stock). Luckily mine is free floating and not full bedded so it was easy to get rid of the barrel ring.
Also check the long screw that sits in the back of your stock. You'll need a special screw driver (i bought one from Builders and grinder the point for a snug fit). Also have good gunsmith check the bridge mount of the scope for you.
It is worth wile to check all screws from time to time.
Some thing else to check is if your scope still have room to set or is it at max at one point

On A different note, you could try 180 gr Sierra Pro Hunters. I load mine with 43 gr S355 and get 15mm groups

[Doekster]

That barrel ring might be some thing to try and get rid of. I battled for a long time with mine (same make and model as yours, fitted with synthetic stock). Luckily mine is free floating and not full bedded so it was easy to get rid of the barrel ring.
Also check the long screw that sits in the back of your stock. You'll need a special screw driver (i bought one from Builders and grinder the point for a snug fit). Also have good gunsmith check the bridge mount of the scope for you.
It is worth wile to check all screws from time to time.
Some thing else to check is if your scope still have room to set or is it at max at one point

On A different note, you could try 180 gr Sierra Pro Hunters. I load mine with 43 gr S355 and get 15mm groups

I have heard nothing but good things about the 180gr Sierra Pro Hunters. I am quite sure the barrel ring needs to go and a diffrent approach needs to be taken regarding the full bedding.

We will let a gunsmith have a second look at the scope mounts. I know exactly what you mean with the long screw at the back of the stock. A screw driver was also sacrificed to be modified to fit that screw 100%.

Are your barrel completly free floated? Why I ask is because the 303 barrels are known to be very flexable barrels and normally needs at a presure point somewhere along the barrel.

What I have read about the bedding option one have when free floating the barrel is that it should have about 5 pounds of upwards preasure on the front end of the stock. Then the barrel is free floated from the chamber to about 1 inch before the forend of the stock. This does make sense if on think about what function the original military full stock's front metal piece did. It pushed up the barrel and provided upwards preasure.

[jdpretorius]

Hi Doekster, jip, my barrel is completely free floating, no issues .... 3 shots max at a time.
I tweaked a couple of things. My barrel's crown was a bit worn so I sacrificed 6mm and had an inverted crown cut (competition crown) I also had the 2 cams on the trigger polished for a smoother pull.
I'm no expert but It sounds like some thing must be loose or putting pressure on the barrel or action at some point

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[jdpretorius]

If it was my gun... I would have suspected that it is the front stock that is flexing a bit from hot to cold. Mine was twisted slightly

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[opalsasquatch]

Good day opalsasquatch

The stock is an ATI synthetic stock, can humidity/temerature change still influence this?

No, not like wood can, but a synthetic stock can be rather flimsy depended on how it is constructed, meaning that how the rifle is supported during shooting can make fairly large changes in POI
Example: a bipod can force a stock into the barrel and change harmonics. If it is twisting enough, even a couple inches either way in a front rest can make a difference.

However, after reading some other posts before this, I think the barrel band is just as likely to cause problems

Hope you get sorted