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Bcraft1111,
Bolt sleeving is a proceedure that is used to tighten up the bolt body fit in relation to the receiver bolt way.
If you take a Rem 700 receiver, there will be anywhere from around 0.006" to the worst I have seen, 0.015" clearance between the bolt body and the baring surfaces of the bolt way in the receiver.
Even if an action is perfectly trued, there will still be a canting of the bolt body occuring when the rifle is in the cocked position.
The reason, when the striker assembly is retained in the rear(cocked) position, it is held there by the sear suface which ingages the striker assembly at an angle on the bottom of the bolt. This angle is needed as it not only hold the striker back but it also powers the sear down against the trigger so it will not slip off.
The angled surface retaining the striker assembly forces the striker assembly and thus the entire bold body vertically until it is stopped by the top baring surface of the receiver bolt way.
As I stated earlier, this can vary from anywhere from around 0.006" to 0.015".
What happens as a result of this lifting of the rear portion of the bolt body is that because the front of the bolt as some tension against the bolt face from at least the plunger assembly and generally but the case contact in the chamber. As a result, the forward section of the bolt does not life.
So now we have a bolt that is cocked, ready to fire. The rear portion of the bolt body is higher then the front of the bolt body because the rear has been camed up and the bolt will pivot if you will around the front baring surface of the bolt and receiver.
What this canting does is actually lift the top bolt lug baring surface off its mated locking lug recess in the receiver.
So even though we have maticulously printed this receiver, when the rifle is cocked ready to fire, only one locking lug is baring solid. This will occur even with perfectly lapped in lug baring surfaces.
When the trigger is pulled, the sear drops and allow the striker to start moving forward toward the firing pin, but it also allows the entire bolt to drop from its elevated position and as such when the striker lands on the primer, it will often be in a different location from one shot to another.
The vibration pattern will also be different in the bolt body as a result of this bolt drop.
Sleeving greatly reduces this problem.
You take the bolt and set it up in the lathe and take releif cuts just ahead of the bolt handle and just behind the bolt lugs. These are not long cuts, generally around 1.200" long for the rear and around .400" for the front. They are also not overly deep cuts, just enough to hold a sleeve in place.
Then two bushings made of either 4130, 4140 or 416 stainless are split and fitted to the bolt body. These halves are epoxied in place using either Brownells Steel bed or plain old J-B Weld.
They are allowed to set up for 15 hours or so and then they are turn down to match the bolt ways of the receiver. The tighter the fit, the slower the bolt will need to be worked to prevent bolt binding. This is especially true with a double sleeved bolt, front and rear. This system is generally used on target and varmint rifles where paniced working of the bolt is not an issue.
For big game hunting, I highly recommend only sleeving the rear surface. It still does a great job controlling bolt lift and the bolt will also work much smoother in an excited state. Results in consistancy are very close to but not quite equal to a double sleeved bolt but vastly superior to a non sleeved bolt.
Again, bolt sleeving is just one part of a properly accurized receiver. ITs like deburring your flashholes on your cases. Alone, it will not make a drastic difference on target, combined with all the other accurizing proceedures, it will add up to as consistant an action as you could possible have built.
Now for a big game rifle that is designed for easy carrying and for shooting off hand out to 300 yards, the benefits of this will not be realized even though they will be there. There is simply to much human error when shooting off hand to see the results.
Good Shooting!!!
Kirby Allen(50)
Bolt sleeving is a proceedure that is used to tighten up the bolt body fit in relation to the receiver bolt way.
If you take a Rem 700 receiver, there will be anywhere from around 0.006" to the worst I have seen, 0.015" clearance between the bolt body and the baring surfaces of the bolt way in the receiver.
Even if an action is perfectly trued, there will still be a canting of the bolt body occuring when the rifle is in the cocked position.
The reason, when the striker assembly is retained in the rear(cocked) position, it is held there by the sear suface which ingages the striker assembly at an angle on the bottom of the bolt. This angle is needed as it not only hold the striker back but it also powers the sear down against the trigger so it will not slip off.
The angled surface retaining the striker assembly forces the striker assembly and thus the entire bold body vertically until it is stopped by the top baring surface of the receiver bolt way.
As I stated earlier, this can vary from anywhere from around 0.006" to 0.015".
What happens as a result of this lifting of the rear portion of the bolt body is that because the front of the bolt as some tension against the bolt face from at least the plunger assembly and generally but the case contact in the chamber. As a result, the forward section of the bolt does not life.
So now we have a bolt that is cocked, ready to fire. The rear portion of the bolt body is higher then the front of the bolt body because the rear has been camed up and the bolt will pivot if you will around the front baring surface of the bolt and receiver.
What this canting does is actually lift the top bolt lug baring surface off its mated locking lug recess in the receiver.
So even though we have maticulously printed this receiver, when the rifle is cocked ready to fire, only one locking lug is baring solid. This will occur even with perfectly lapped in lug baring surfaces.
When the trigger is pulled, the sear drops and allow the striker to start moving forward toward the firing pin, but it also allows the entire bolt to drop from its elevated position and as such when the striker lands on the primer, it will often be in a different location from one shot to another.
The vibration pattern will also be different in the bolt body as a result of this bolt drop.
Sleeving greatly reduces this problem.
You take the bolt and set it up in the lathe and take releif cuts just ahead of the bolt handle and just behind the bolt lugs. These are not long cuts, generally around 1.200" long for the rear and around .400" for the front. They are also not overly deep cuts, just enough to hold a sleeve in place.
Then two bushings made of either 4130, 4140 or 416 stainless are split and fitted to the bolt body. These halves are epoxied in place using either Brownells Steel bed or plain old J-B Weld.
They are allowed to set up for 15 hours or so and then they are turn down to match the bolt ways of the receiver. The tighter the fit, the slower the bolt will need to be worked to prevent bolt binding. This is especially true with a double sleeved bolt, front and rear. This system is generally used on target and varmint rifles where paniced working of the bolt is not an issue.
For big game hunting, I highly recommend only sleeving the rear surface. It still does a great job controlling bolt lift and the bolt will also work much smoother in an excited state. Results in consistancy are very close to but not quite equal to a double sleeved bolt but vastly superior to a non sleeved bolt.
Again, bolt sleeving is just one part of a properly accurized receiver. ITs like deburring your flashholes on your cases. Alone, it will not make a drastic difference on target, combined with all the other accurizing proceedures, it will add up to as consistant an action as you could possible have built.
Now for a big game rifle that is designed for easy carrying and for shooting off hand out to 300 yards, the benefits of this will not be realized even though they will be there. There is simply to much human error when shooting off hand to see the results.
Good Shooting!!!
Kirby Allen(50)
