Change in grouping after bedding

JockStalk

Well-Known Member
Before bedding;

home loads 1/2” five shot group
factory 1 1/2” five shot Group

After bedding;

Same home loads 1 1/2” five shot group
Same factory 1/2” five shot group

anyone else had the same???
 

Conh

Well-Known Member
As srvet said, rework the load. You are essentially now shooting your home loads through a different rifle and the loads need working up accordingly.
 

Muir

Well-Known Member
You were getting .5 MOA from handloads and decided to "bed" the rifle?? I had a friend glass bed and free float a SAKO 7mm Rem Mag. He went from 5/8 MOA to 1.5 MOA so your problem isn't uncommon.~Muir
 

Woodsmoke

Well-Known Member
What made you decide to bed it if it was shooting well beforehand? (Not having a dig, I'm genuinely curious)
 

Yorric

Well-Known Member
I used to have a Ruger M77 Mk1 V in 308 flavour. It shot sub MOA all day UNTIL I bought a Timney trigger for it & decided whilst I had the stock off to free float the barrel which had come with a bedding point at the front of the fore-stock. --- I rebuilt it & couldn't get the groups below 4" -:doh:-

- Sooo I pulled it apart & replaced the front bedding -- Result -- sub MOA once again! :D PHEW!

That old saying springs to mind -- "If it ain't bust, don't mend it!"

Ian
 

JockStalk

Well-Known Member
Decision to bed it? Timber stock was beginning to show signs of compression and washers were an interim solution but not pretty, so decided it needed pillars. And if it was getting pillars why not bed it.....

You know how these things start to snowball. Not saying its right, its just what happened.

Its now gone from being a bit shoogly to being rock solid. Will give the load a rework (but no hurry seeing as the factory rounds are good!)
 

Muir

Well-Known Member
I used to have a Ruger M77 Mk1 V in 308 flavour. It shot sub MOA all day UNTIL I bought a Timney trigger for it & decided whilst I had the stock off to free float the barrel which had come with a bedding point at the front of the fore-stock. --- I rebuilt it & couldn't get the groups below 4" -:doh:-

- Sooo I pulled it apart & replaced the front bedding -- Result -- sub MOA once again! :D PHEW!

That old saying springs to mind -- "If it ain't bust, don't mend it!"

Ian
This is what happened with my friends SAKO. He was amazed that such a highly rated company as SAKO would neglect to router out a pad of wood in the for end! He promptly sanded it away and viola! Crap. When he came by to ask advice I told him to call SAKO's parts department and ask if he could buy that little pad of wood because it was supposed to be there. He came back later and said that he actually called the US SAKO distributor at the time and they said it should have 5# of pressure on the wood. I put a pad of glass with the 5# pressure and like you, his groups shrunk back to where they had been.... or so he told me.~Muir
 

1894

Well-Known Member
Pillar bedded my sako 243 because poi with bipod changed an inch or so compared to without.

Rifle shot to same poi with bipod as without after by virtue of the fact that the ragged hole without bipod was within the 6" group it now shot with the bipod.

This cured me of fixing unbroke things and using bipods!
 

1894

Well-Known Member
Pillar bedded my sako 243 because poi with bipod changed an inch or so compared to without.

Rifle shot to same poi with bipod as without after by virtue of the fact that the ragged hole without bipod was within the 6" group it now shot with the bipod.

This cured me of fixing unbroke things and using bipods!

This was the same rifle I replaced a perfectly good 22" barrel with a 26" custom to get more velocity. I got more velocity but only with lower bc bullets that had the same trajectory as with the 22" barrel.

Taught me a lot that rifle
 
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ejg

Well-Known Member
The only reason why a rifle is pressure bedded is to bend a crooked forend straight so that the "Stalkers quality test" "small barrel forend gap and even spacing" is met. An injection moulded plastic stock or a wooden stock will not hold a consistent pressure, if the forend pressure is constantly changing with temperature or moisture content what good is that to accuracy. Target shooters, Precision rifle shooters, Sniper rifle manufacturers have all recognised the fault in the theory and gone away from pressure bedding.

I don't dispute that under bench rest conditions pressure bedded rifles can shoot very well but I refuse to accept that a rifle with varying pressure applied on the barrel will shoot to the same POI. Especially dynamically used rifles that have differing shooting positions will not shoot to the same POI as free floating barrels..... unless you have good shooting training. I bet if one would look at the shooting style that Muir with his experience of pressure bedded rifles has one will recognise how the style physically overcomes the flaws of the rifle.
Funny that everyone accepts the fact that a rifle will change POI if you rest the barrel on an object but think there is a difference to rest it on the forend of a pressure bedded rifle. Fact is the resting pressure on a forend of a pressure bedded forend will 1:1 transfer the resting pressure onto the barrel, just as if resting the barrel directly on a surface.

We build hundreds of stocks year that are free floating and factory pillar bedded which use light weight hunting barrels. I can't even remember of any complaint in the accuracy department. Often our customers send in pictures of groups which are under 1/4" with factory T3 lite rifles. Recently a customer picked up an ex demo stock from us, put it on his T3 and won the Stags shoot in the midlands. That stock was factory epoxy bedded.

I believe the problems that are mentioned after bedding have a different reason. Bedding a rifle is not as simple as some think. Like SRVET said the ammo might need to be fine tuned again. If a bedding is done well this will not bring a rifle from 1" to 6" groups, something else is wrong.
We have also had a long learning curve when it came to bedding stocks, made many mistakes and still learning what not to do.
edi
 

Colin G

Well-Known Member
My T3 changed harmonics after 500 rounds the groups opened up and I couldn’t understand why as nothing else had changed my theory is that it had shot in and I just tailored my reloading to 1/2 a grain more and extended to mag length I was then and now back on 1/4 groups and less on good day
 

JockStalk

Well-Known Member
Been a bit overworked of late - but finally got out with a new ladder of loads to try.

Loading I used before bedding remains about 1.5" groups. Found load that tightens group up again - back in love with the old girl.
 
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