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B14R Bolt Shims

7K views 15 replies 11 participants last post by  jim46ok 
#1 ·
A while back I read somewhere that Bergara was planning on offering a shim pack for the B14R bolt that would allow the owner to adjust the headspace to better fit the ammo being fired....I googled it, and found that someone is already offering a kit.

https://www.triggershims.com/Bergara_Rimfire.php

So, I thought I would test it out. Ordered 12 pack assortment on Saturday evening. They arrived in the mail today (Tuesday) from Michigan. And here I thought USPS was supposed to be slow and unorganized...

I won't be able to test them out for a few days (maybe a week or more...it's hot as hell in AZ, and I don't want to go outside).

Anyways, I'll let you all know what I find out when I try it.
 
#2 ·
I shimmed both of mine .003. Probably should have done some true before and after but the weather had been bad and I couldn’t wait. Did not have a means of measuring headspace so pulled a bullet of a live round to check. .005 had slight contact on closing. My plan was to give Eley a few thousandths clearance but used CCI for the added clearance. Guess I need to get back around to testing that.
 
#3 ·
So, I need know the best way to check the headspace on a 22 B14R (besides disassembling the bolt, adding a 0.001" shim, reassemble, shoot some test rounds, repeat...a lot).

I should also figure out how to take the bolt apart, but that will be the easy part. It would also be nice to know the factory measurements for headspace and what exactly the chamber is cut for...my bolt measures out to have 0.0785" of play in spot for the shims, so no danger of running out of room to play with.

All I know right now, is that if I check a live round, there is significant lands/grooves on the bullet.

Headed to the range tomorrow AM, but I won't have time to test out the shims on this trip...this time I'm just interested a making a few 6x5's on different ammo.
 
#13 ·
Bergara B14R Headspace

So, I need know the best way to check the headspace on a 22 B14R (besides disassembling the bolt, adding a 0.001" shim, reassemble, shoot some test rounds, repeat...a lot).

I should also figure out how to take the bolt apart, but that will be the easy part. It would also be nice to know the factory measurements for headspace and what exactly the chamber is cut for...my bolt measures out to have 0.0785" of play in spot for the shims, so no danger of running out of room to play with.

All I know right now, is that if I check a live round, there is significant lands/grooves on the bullet.

Headed to the range tomorrow AM, but I won't have time to test out the shims on this trip...this time I'm just interested a making a few 6x5's on different ammo.
My Begara B14R headspace is .0415". I determined this by making a brass cylinder with a rim and machining the rim thickness down until the bolt would close.

I ordered the bolt shim kit and intend to add a .002" shim to bring the headspace down to .040". I shoot Lapua and SK match ammo which has a rim thickness of .040".
 
#5 · (Edited)
Auto part Font Engineering Camera accessory Metal


Found a picture for you. Knock roll pin out after removing the cocking piece/ spring assembly. Once you add shims Put roll pin back in. Check for friction When lowering the bolt without spring assembly. I pulled a bullet out of a live round to check. I installed the .005 first and was basically zero headspace. Just went to .003 in both did not even check the second gun.
 
#6 ·
Any updates? Did it improve the grouping?


Was the headspace adjustments for a specific ammo ? Looking for any info on shim thickness vs. brands of ammo. And if this helps tighten groups at longer ranges.

Im new to precision 22 shooting and just got my B14r last month and the ammo shortage has kept me from testing more brands. Ive tried Aguila Rifle match and its ok at 50 but when I go to 100 yards its probly about a 2-3inch groups. Wolf Match Extra was almost about the same, but I really only tried about 10-15 rounds. I probly need to shoot a box or two and really see what it will do. I have 1000 rds of Norma Tac22 coming this week.
 
#7 ·
Bergara Headspace



I made a headspace gauge out of brass with a rim thickness of .044" and tried it in my Bergara B14R. The bolt would not close (I removed the striker assembly to make testing easier). I then machined the rim thickness down on my gauge until the bolt would just close. The headspace was .0415"

I shoot Lapua Center-X and SK Rifle Match and both have a rim thickness of .040" to .041" so I guess I am all set.
 
#9 ·
I have measured the recess in the bolt face then taken lead fuse wire , twisted , places the fuse wire on the breach face ( lightly grease the bolt and breach faces ) and close the bolt smashing the lead wire , measure the smashed fuse wire thickness with dial micrometers and add that to the bolt face recess dimension .
 
#10 · (Edited)
thanks

:bthumb: thanks for posting the shim link, I ordered some for my B14R I do have a proper .42 headspace gauge which I use in conjunction with .001 shims to check and get my readings, but it's too hard to cut up bolt shims, so when they are already made, that's so easy:) we are in lockdown here in Australia and have been for 10 weeks on the east coast so one day I guess Ill be able to go to the range and shoot my B14R again
 
#11 ·
The B14 R is a CIP-spec rifle. CIP specs call for a headspace of .043". So does SAAMI. For what it's worth, the noted gunsmith Bill Calfee puts the HS on the rifles he builds at .043". Calfee said the following in his book and elsewhere: If your headspace is safe, and if you have killer ignition with it, the headspace itself, no matter what it is, has absolutely nothing to do with rimfire accuracy.

There are no shortcuts to improved accuracy. Rather than changing HS by .001" or .0015", a more practical path to better accuracy, no matter the rifle so long it's capable, is to find better ammo. It's not the name on the box that counts either. Different lots of the same variety of ammo perform differently. Find the lot(s) that suit the rifle. It's not the quick fix many shooters may be looking for, but it's the only one that can work if the rifle and shooting is sound.
 
#14 ·
no gain

We worked with this in Jan-March this year.

we saw no consistent gains with any ammo we tested. (Eley subsonic/Tennex, SK RM/Biatlon/HVRM/Standard, RWS /Club, CCI Greentag, Aguila match [blue&gold box]

Take me at my word, you're headed into the land of diminishing returns.
 
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