No4 barrel bedding sharing

[Frederick303]

Competition shooting would not have adopted the centrally bedded rifle if it was not a good method that provided good groupings with consistent zeros. Having central bed a number of rifles successfully, be aware that a good central bedding is not a simple process. The first thing you have to be aware of is that the upward pressure is rather crucial and will have an effect of the groups. If the pressure is too high and you lift the barrel reinforce off of its bearing you will have poor accuracy (large group). If it is too low you will have all sorts of variable vertical stringing. I have had to mess with the pressure loading at the central bearing on a few rifles to get the best grouping.

I have also seen a difference in the location of the central bed, with three locations being possible, 5.5 inches ahead of the chamber (on the first solid wood area), 7.5 inches ahead (middle of the second lighting cut) the and finally at the middle band 12 inches ahead (under the middle band). In my experience bedding under the middle band is the least advisable, unless you add some packing (aka South African method) to the front barrel bearing surface (normal bedding location). Under this scheme the central bearing is more of a damping bearing then a rigid bearing and needs some sort of flexible material such as graphite/greased cork between the bearing on the wood and the barrel.

Having used the No 4 Mk I and No 4 Mk II in competition (US NRA style) I can tell you that a properly central bedded No 4 is a much better competition rifle then a conventional bedded No 4, due to the fact that the central bedded rifle has much less group shift due to sling pressure. This is true if you use the conventional US single point sling or the British 2-point sling locations. Further once correctly bedded and grouping well, the rifle holds its zero far better over temperature and humidity then a conventionally bedded rifle. I have seen subtle shifts in point of aim between a match tuned front bearing No 4 MK I in winter and summer that one does not see with a centrally bedded No 4.

Be aware I have never fired one of these rifles over 300 yards, so how well the bearing hold up at 600 yards is something I might be wrong about, but the source of my information told me if you get a good grouping at 200 yards with a central bedded rifle it will group equally well at 600, assuming ammunition with normal velocity variations.

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[Thunderbox]

Having used the No 4 Mk I and No 4 Mk II in competition (US NRA style) I can tell you that a properly central bedded No 4 is a much better competition rifle then a conventional bedded No 4, due to the fact that the central bedded rifle has much less group shift due to sling pressure. This is true if you use the conventional US single point sling or the British 2-point sling locations. Further once correctly bedded and grouping well, the rifle holds its zero far better over temperature and humidity then a conventionally bedded rifle. I have seen subtle shifts in point of aim between a match tuned front bearing No 4 MK I in winter and summer that one does not see with a centrally bedded No 4.

Be aware I have never fired one of these rifles over 300 yards, so how well the bearing hold up at 600 yards is something I might be wrong about, but the source of my information told me if you get a good grouping at 200 yards with a central bedded rifle it will group equally well at 600, assuming ammunition with normal velocity variations.

Thats really an opinion, not an accurate statement of fact. Many of us find that properly adjusted standard bedding is just as good - certainly at 300 to 1200 yards. I've tested hundreds of No4s, and the majority of the best ones were standard. Centre-bedded rifles have slight statistical advantage in a equal size sample of rifles picked at random - but thats probably just because most of them were built with selected barrels in the first place and had a gunsmith set the bedding, whereas standard No4s have any old barrel and may not have been checked since they were last in service.

I don't think temperature or humidity has much if any effect in most Enfields; they are stocked with seasoned wood and - of course - the barrel heat alone quickly outstrips any environmental effects.