Rem 700 Bolt Mod

[jesilva]

Is there an accepted method for making the bolt easier to close. It seems that it takes extra pressure to override the notch on the bolt body. Is it acceptable to lighten/shorten the mainspring at all.

 

[carlsbad]

Many "custom" actions work hard to make this function smoother. As a result, I have replaced firing pin springs on many of them over the years with stiffer springs when owners had FTF problems. But a lighter spring will work with some primers etc. it just depends on how willing you are to play with primers etc. The most problems I've seen were with military primers, specifically M118LR.

Also, take your bolt apart and make sure the threads are very clean and lubed. The bolt turns on these threads while cocking.

There are lots of spring upgrades and improvements available. YMMV.

--Jerry

 

[Ggmac]

Need more info . What action ( rem or clone ), what length , new or used . What use are you going to put it to ( hunting , target , bench rest , tactical ) any modifications already done ( trig, timing , bolt body , extractor )
Gary

 

[Alex Wheeler]

Your Remington has about . 050" cock on close. which is how they are designed . the action can be timed to eliminate that. a smooth one finger close is the result . never lighten a firing pin spring. if you want to just make a little improvement you can remove the bump in the ramp after the notch and put a good chamfer on the leading edge of the lugs .

 

[DaveTooley]

What Alex said. Never alter a perfectly functioning ignition system. I wouldn't adjust for the little bit of cock on closing unless it's severe after other modifications. Beware of unintended consequences.

 

[BoydAllen]

It may be obvious to most, but I have seen rifles that needed their shroud threads and cocking cam greased. For these applications grease is the proper lubricant, not oil.

 

[JasonT]

Alex, can you clarify what you mean by the "leading edge of the lugs?" Do you mean the first part of the lugs' bearing/contact surfaces to engage the receiver on lockup?

 

[Dans40X]

referencing a RH action-
Cut an .080" 45 degree chamfer/break on RH lower & LH upper aft end of bolt lugs w/ a #4 cut needle file.
Blend the 45 degree chamfer/break to a radius w/ a #6 cut needle file.
Chamfer/break 6 other lug edges w/ #6 cut needle file.
Chamfer/break fwd & aft lug radial edges.
Chamfer/break fwd & aft ends of anti bind slot in RH bolt lug w/ tree shaped carbide burr.
Confirm that no burrs left behind w/ a Q tip.

Blend out 90% of the "Peak"/mound between firing pin cocking cam & striker detent in aft end of bolt body.

Adding "arm" & "moment" to your bolt handle is not the cure.
Locate,Time the bolt handle for primary extraction & into battery.
Time striker to sear "hand off"

.050" cock on close is an assumption & is dependent on bolt/firing pin assy vintage & trigger group installed.

2 finger bolt manipulation is the preferred method to cycle a bolt action.

 

[jesilva]

This is completely stock Rem 600 action/bolt. It just felt it needed a little more effort to close than my other 700's. I have taken the bolt apart and polished the firing pin shaft and greased the threads. However, I have not polished the threads. I was not sure if the locking notch could be relieved any and I did not want to alter the bolt in a way that could not be fixed. The issue is not a major one, I was just curious. Thank You

 

[butchlambert]

This is completely stock Rem 600 action/bolt. It just felt it needed a little more effort to close than my other 700's. I have taken the bolt apart and polished the firing pin shaft and greased the threads. However, I have not polished the threads. I was not sure if the locking notch could be relieved any and I did not want to alter the bolt in a way that could not be fixed. The issue is not a major one, I was just curious. Thank You

Sir, you may want to pay attention to Dan.

 

[Alex Wheeler]

Alex, can you clarify what you mean by the "leading edge of the lugs?" Do you mean the first part of the lugs' bearing/contact surfaces to engage the receiver on lockup?

Your just rounding the edge of the lug that rides up the closing cams inside the action. Some actions, like a stiller come this way. It helps some. Unless the ignition timing is modified to eliminate cock on close you will always have resistance to close the bolt. Do not just grind or file the cocking piece to eliminate cock on close, thats only a small part of the job. If there is .050" cock on close and you remove it, you also removed .050" firing pin fall. Not good if top accuracy is your goal. You have to do the whole job to re-gain that pin fall.

 

[jesilva]

I agree with rounding the edges of the bolt head to allow them to engage easier. I just did not know how much.

 

[Hal]

referencing a RH action-
Cut an .080" 45 degree chamfer/break on RH lower & LH upper aft end of bolt lugs w/ a #4 cut needle file.
Blend the 45 degree chamfer/break to a radius w/ a #6 cut needle file.
Chamfer/break 6 other lug edges w/ #6 cut needle file.
Chamfer/break fwd & aft lug radial edges.
Chamfer/break fwd & aft ends of anti bind slot in RH bolt lug w/ tree shaped carbide burr.
Confirm that no burrs left behind w/ a Q tip.

Blend out 90% of the "Peak"/mound between firing pin cocking cam & striker detent in aft end of bolt body.

Adding "arm" & "moment" to your bolt handle is not the cure.
Locate,Time the bolt handle for primary extraction & into battery.
Time striker to sear "hand off"

.050" cock on close is an assumption & is dependent on bolt/firing pin assy vintage & trigger group installed.

2 finger bolt manipulation is the preferred method to cycle a bolt action.

Dan
A lot of good info.
Thanks for sharing.

Hal

 

[JasonT]

Alex - thank you very much!! I'll add this to my usual accurizing routine whenever there's excessive bolt-closing force required.

 

[lloydx2]

We are extremely lucky to have so much good info coming
from so many good sources. Thanks Lloyd
Alex, Congrats on your dasher builds for Mousel

 

[Alex Wheeler]

We are extremely lucky to have so much good info coming
from so many good sources. Thanks Lloyd
Alex, Congrats on your dasher builds for Mousel

Thanks, but Tom was breaking records long before I built his rifles. I can not take any credit for his shooting.

 

[kendog]

.....
Time striker to sear "hand off"

.050" cock on close is an assumption & is dependent on bolt/firing pin assy vintage & trigger group installed....

Can you elaborate on these points?

 

[Dans40X]

kendog-pm inbound.

you tube producer-
is it the pin's fall
or
does the spring have any influence?

You may want to do some reading/research from the late,great Palmizano-Pindell of PPC fame.
Their equation has stood the test of time since the mid 70's & holds true to this day.

 

[Alex Wheeler]

kendog-pm inbound.

you tube producer-
is it the pin's fall
or
does the spring have any influence?

You may want to do some reading/research from the late,great Palmizano-Pindell of PPC fame.
Their equation has stood the test of time since the mid 70's & holds true to this day.

Dan,
Not sure what your asking. There are 3 sources I trust when it comes to ignition energy, George Kelbly, Jim Borden, and Jerry Stiller. These men have tested ignition energy and its effects. All three agree you cant make up for short pin fall by adding more spring. Jerry has some old postings where he expresses concern of anything less than .230" on a Remington style ignition. I will not let anything go with less than .240" fall, a factory weight spring, and full weight firing pin. Until I perform my own testing which I have planned I wont go any less on fall. Bat actions run about .210" fall. Mr Boyer proved in a tunnel with his rail, that there was an improvement in accuracy with more energy. They added weight and spring on the new actions. The ppc game is a little different because the federal primer is almost standard and is one of the softest primers. I mostly do long range Br and F-class. Magnum primers are more common and harder to set off. While it would be much easier to just cut the cocking piece and add spring, I am not comfortable doing that.