New 22LR Match Barrel, Headspacing questions

[littlepod]

So I got a new barrel for my Tikka T1X bolt action and I was trying to figure out if I'm headspacing correctly. I have a tight Winchester 52D chamber and I can't even push a round in my hand, so I basically would put the barrel in, tighten it down, and cycle the bolt, see if there's a gap, and rinse and repeat. Initially it was really hard to push the bolt all the way forward so I could close it, so I undid everything and tried to loosen up the headspace a bit. It was easier to cycle the bolt, but then I was getting light strikes and 50% of my shots wouldn't fire. So I lessened the headspace.

I've shot 350 rounds through it now, and 0 failures for feeding, firing, or ejecting. But cycling the bolt does take some oomph. I need to make sure I push forward with enough force to get the bullet seated. Otherwise the bolt isn't far enough to allow for it to close. Shooting prone is okay, I just put a little more effort, and I can get back on target pretty quickly. I went to a bench, and without gripping bipod legs that I had in prone, it was a bit harder to chamber a round. I worry that this will most likely affect me during positional and barricade shooting, I also don't know how much of it is headspacing issue, versus just a tight match chamber. I saw someone with a brand new anschutz and they had a very similar experience where they had to put a bit more effort into loading the round.

I inspected all the ejected rounds, and I didn't notice any rims "crushed". I did notice that sometimes feeding I could tell the bottom of the bullet, right where it meets the brass, and has those lines, like where the red is, right around there gets scraped on the barrel.

Thoughts?

Headspacing is such a fractional amount that doing it by hand trying to wiggle the barrel a little more is such an imprecise way of doing it... so I wonder if there's just an easy way to do it "right".

Thanks in advance.

 

[Dolomite_Supafly]

Ideally the rounds should be engraved by the rifling. That is what you are probably seeing. It should also have a minimal amount of side to side movement.

I would find the best shooting ammo then set the headspace to that rim thickness. Almost all ammo use a slightly different rim thickness.

I use standard Bentz for semi auto and Lilja for my bolt guns.

With a Lilja chamber my guns have a lot resistance.

I machine the face of my 10/22 bolts to set the headspace. Standard is like .055” but most rims are under .045”. I find the ammo the barrel likes the machine the bolt to set headspace. I even machine the breech face of a factory 10/22 barrel until the bullet gets engraved. It helps accuracy without sacrificing reliability.

 

[pete_f]

On a .22 LR, the nominal SAAMI headspace dimension is .043. This is the dimension from the bolt face to the surface of the barrel that the cartridge rim contacts. In order to set or check headspace on a .22LR or any rimmed cartridge chamber, you must have at least one or preferably a set of headspace gauges.
In a .22LR chamber, headspace has nothing to do with how much the bullet engraves, this is typically determined by the dimensions of the reamer used to cut the chamber. You indicate that your barrel has a Winchester 52D chamber. If you look at a list of .22LR chamber dimensions, you will find that the 52D chamber is probably the shortest one listed, this worked in a 52 because they have a lot of closing cam. In an action with less closing cam, you will need to push the bolt forward to push the bullet into the throat far enough to get the locking lugs to what ever closing cam it has. I will also point out here that the cartridge base to forward driving band dimension varies quite a bit between the different ammo brands. Hope you find this helpful.

 

[68hoyt]

How hard is it to close the bolt on an empty casing ?

 

[littlepod]

When you mention closing the bolt, do you mean pushing the bolt forward, or camming it down? With an empty casing, pushing the bolt forward and closing it is super easy. With a live round, pushing the bolt forward is harder, camming it down is easy.

I think I have my headspacing correct, just the Win52 chamber requires a bit of oomph to really push the round in, same reason why I can't push a round in by hand. I'm going to shoot a round and compare it to an unspent round to see if the rim is getting crushed at all. Some accuracy people like their headspacing tight enough that the rim is very, very lightly crushed from what I heard.

I think SK rounds feed nominally easier, and they also shoot better so I'm going to pick up the SK variety + Lapua Center-X. All my Eley ammo shot pretty meh... They shot 20% larger groups than my factory barrel. SK ammo though is shooting about 20% tighter than my factory barrel so that's a good sign.

 

[68hoyt]

Mainly I meant camming , if the head space is too tight the bolt will cam down hard as it is squeezing the rim between the breech and barrel , if it closes and cams down on an empty the headspace isn’t tight ( may be too loose though ?) you could check your rim thickness with micrometers and if around .043 use it for a head space gauge, you might have a 52d chamber that the reamer wasn’t inserted far enough ( chamber is cut too shallow ) that would explain the hard push to seat casing