Need Barrel Advice

[NMC_EXP]

My wife shoots rimfire F-Class with a Remington 40X. The rifle appears to have been lightly used, has its original standard weight barrel, and until today (I installed a Shilen Competition trigger) original, 1.5 lb trigger. She uses Lapua Center-X. Her wind reading skill is rudimentary.

If the wind is light and/or predictable she often shoots clean scores at 50 and 100 yards on the reduced ISSF target e.g. five shots into 0.3" at 50 yards and 10 shots into 1.0" at 100 yards.

She recently won a Hart barrel and would like to have it installed on her rifle. This raises a couple of questions:

--How much, if any, group size reduction should typically be expected in going from an apparently good 40X barrel to a Hart?

--To see any benefit from the Hart would it be necessary to use a higher grade of ammunition?

--Harts standard rimfire barrel is now a 3-groove. If you folks were going with a Hart would it be a 3-groove or something else?

--Hart offers 16" or 17" twist rates. For outdoors at 50 and 100 yards what is the current thinking on preferred twist rate? We use Lapua as opposed to Eley or RWS for no particular reason.

I pose the question because I have heard a few horror stories about the occasional new barrel that will not shoot. At her level of development, the factory barrel seems (to me, a mediocre sling shooter) to do very well with mid level ammunition. I'd hate to remove and replace it only to find the new barrel offered no perceptible improvement or was even worse.

[gwsb]

AS I have often said here, you can't fall in love with your barrel. It doesn't know you own it. 40X actions are very good and have the potential to be great guns, but remember an original 40 X barrel is about 40-60 years old and probably shot out.

[beye]

A barrel that can shoot cleans on the F class targets is NOT shot out. How old a barrel is in terms of years does not bear any relationship to how many shots have been through it. It's the mileage and the maintenance, not the year model.
Putting a new barrel on is always somewhat of a crapshoot as to whether it's going to be an improvement or not. Shooting cleans with some regularity with Center X says you have a good shooting barrel. I would focus on improving wind reading skills and save the barrel for later use or trade/sale. There is a lot involved in an accurate .22 match rifle barrel -- good quality barrel, selecting the reamer (there are about 15-20 of them), competent rimfire gunsmith, and finding the right ammunition. Any of these can be the downfall of an accurate rifle. It seems you have one now, so "if it ain't broke, don't fix it". BTW, higher grades of ammunition generally have fewer "flyers" and will help any rifle, with the right brand and lot number. There are no barrels that make lesser grades of ammunition shoot like the top grade consistently.

[NMC_EXP]

beye: My gut feel is the current barrel is a good one.

gwsb: I appreciate the reply.

Brings to mind the diametrically opposed axioms:

-- "If it ain't broke, don't fix it."

-- "If it ain't broke, keep fixing it until it is."

I've been guilty of the second more than the first. Hence my reluctance to rebarrel at this time.

Installed right away or not, I need to order the barrel. Still could use some info on:

(1) 16" or 17" twist and

(2) 3 groove or....?

Thanks

[beye]

16 has been the most popular twist, particular for rifles where 100 yd. is included. Main drawback to odd number of grooves is the difficulty in measuring slug diameter when deciding where to crown barrel. For this reason I prefer 4 or even 6 groove barrels.

[gwsb]

I trust group size much more that score as an indicator of rifle/ammo quality and I don't consider a 1" group at 100 yards acceptable.