Lets talk about receiver tolerances!!

S

skeetlee

Active member
Hey fellas me again LOL!!! The barrel topic when pretty well so now i would like to talk about actions and how there tolerances effect accuracy. This is something i have been thinking about here lately, and i really dont know how to put it in perspective. Maybe you fellas can shed some light on the subject. Ok, I hope i say what i am wanting to say and make some since out of it. I have been thinking about different actions here lately for a 30BR build. I have been doing some homework and trying to educate myself as much as possible about the different offerings out there. What i am finding is that some action have different bolt tolerances for different purposes. Tactical/Hunting actions are a bit more loose than say a benchrest action. I understand why, but what i do not understand is how this effects the accuracy potential. My way of thinking is that when the action is locked up and ready to fire there better not be any slop in the bolt, and i have found this to be true on all my action weather they are rem 700's or custom. Some manufactures claim .007thou play and others .002thou play. But like i said when they are locked up aren't they all equal?? How does the difference in play before lock up effect accuracy if all is equal when it comes time to shoot?
I hope i have explained my thoughts properly here for you fellas. Now before i get flamed, i have been reading and researching the subject. Like i have stated in the past, i enjoy this place and you fellas and i like to talk about this stuff. I am not all that concerned about any of this, but this being the thing i like to do the most i like to learn and educate myself to the fullest. This is just something i have been wondering about here lately. thanks Lee

PS By the way i choose a Lawton 7500 for the action on my 30BR. I hope i did ok!!
 
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Just to throw another fly in the pie, the Savage action is rather loose in the receiver, but has a floating bolt head. The floating bolt head allows the bolt face to line up flat with the case head. The rear end of the bolt can wiggle around a bit. And the sear release is on the side of the bolt and not the bottom. Maybe that is why they shoot so good for a factory rifle.
 
Just one instance and you can't make a rationalization from one case. I built a 6.5/284 on a customer's Winchester 70A action. I set the action up in the lathe trued it and trued the bolt. The bolt was sloppy and had about .007 to .010 clearance on the raceways. The lugs were square to the receiver centerline. The receiver threads were concentric to the receiver centerline and the bolt lugs and face were square to the bolt body. The rifle shot 5 shot groups with a few groups in the teens and routinely in the .25" area. This one rifle goes completely against the current trend in having the bolt fit in the raceway as close as possible, .001" or under. It would flat shoot regardless of the slop in the raceway. I don't know how consistent the rifle was, but it shot plenty well enough for a hunting rifle. Probably well enough that my guess is the barrel was wore out on shooting paper and not hunting.
 
I'm interested in this also!

I have some cash finally and am considering buying a used rifle versus "building" one from a Savage action.

So sure a Viper/Stolle/Lawton new precision benchrest action is the best, but just exactly how much worse is a "trued" Savage or trued (or sleeved?) Rem 700?

Will a "trued" regular Savage be better than their "target Action" straight from the factory?

How much difference does it make?
 
These type items have come up many times. It would behoove you to search the archives first. Sometimes it almost appears that somebody enjoys seeing their post rather than seeking info. If I have misread you I am sorry. Read through the archives first and then post questions.
Butch
 
Butch
I did look and i knew you were going to say that!! So i looked twice. I clearly said that i was simply making conversation because i enjoy the sport. If you dont like what i type then please dont participate. I am also sure that your a man of knowledge about this topic and you could probably shed so light on the subject. I know i type to much, but like i said i enjoy this stuff, as do many others here. I dont mean to be in a bad way towards you, but you say the same old thing every time i bring up a subject. Help us new guys out man!! All i do is think about rifles and reloading and shooting and how to get better at what i enjoy doing. I try not to over step my bounds here, but what can i say, i have the passion or the sickness. LOL!!! This topic has been a concern of mine here lately so i thought i would see what the fellas here had to say about it. I apologize !!! Lee
 
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A friend built a rifle on a Remington that had a bolt that was looser than it should have been. He fought with it until he sleeved the bolt at which point it began to shoot as it should have all along. You should have heard the guesses about why it would throw a shot every so often.

There are other places that an action should be closely fitted. I believe that Wilbur had a very high round count Panda go sour until the shroud was replaced. There has been some discussion of the importance of fit in this area.

Mike, I forget, does the Winchester have the same bolt jacking angled sear setup as a Remington?
 
Cocked and locked

Lee- there is always some amount of play while in battery.

Consider that a stiff ejector spring can cause accuracy to degrade.

In a typical factory Remington, this is easy to see. In a BAT, it may be harder to measure......BUT in BENCHREST you fight for that last .001.

BR is an expensive sport, too expensive to compromise on the launching platform......Too many variables.....eliminate as many as you can.

I don't mind second guessing if I dropped enough clicks on that last load, or should I have stayed with my original condition that last match......BUT I don't want to second guess my action choice......not for $300.

If you doubt your 700's have slop in battery, why does your bolt handle jump on firing on an empty chamber?
 
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How does the difference in play before lock up effect accuracy if all is equal when it comes time to shoot?
Click to expand...
I think of it as the amount of force the slop can generate. The more slop it has, the more force it will generate. Kind of like dropping something from a higher height. After the trigger is pulled, the bolt drops and is not forced up any longer. It clicks hard before the bullet is fired and I think this sometimes causes the point of aim to move, we just can't see it because it happens so soon before the bang.

The guys here were discussing ways to tighten the shrouds up because of flyers. I hadn't learned that trick yet and it came to me to simply build up the threads with bronze or silver solder then recut them. A buddies 700 F Class rig had flyers at every range, great shooting rifle except for that. I bronzed over the threads and recut them for a tight fit to the bolt. It hasn't had a flyer since.

http://www.benchrest.com/forums/showthread.php?t=60743
 
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PEI Rob
thanks for the link. This was an eye opener for me. I never gave much thought to this area of the action. Makes since!! See I did learn something!! Thanks Lee
 
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