Bolt lug contact questions

Peecos

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I have a 1977 issue Remington 700 BDL short action that’s giving me a headache. Purchased used on the EE here it’s in excellent condition but just would not provide satisfactory accuracy in the shoots anything into tiny bugholes .222 Remington. A bore scope showed a few small pits on the edges of the rifling but nothing major. Lots of different bullets, powder and primer combinations tried and not what I was looking for. It’s MOA so maybe my expectations are to high. Groups of 5 round always have one or two flyers or two separate groups. My desire for an accurate .222 was high so on goes a new custom barrel! Well it’s doing the exact same thing but I’m still working on different powder/primer combinations at the moment. Yesterday it occurred to me to check the bolt lugs for even wear and there is none! It’s 45 years old and shows typical wear on other friction points on the bolt but not on the rear of the lugs. If I use a sharpie on the lugs to check for contact should I remove the firing pin assembly? Should I have a new or fired in this gun piece of brass in the chamber? I’ll get some pictures to post for visuals a little later. Cheers
 
I think you can keep the firing pin assembly in place since you want to simulate as if you were shooting and the spring is what applies pressure to the lugs before ignition. Brass is optional since factory ammo is usually min spec and does not put much pressure on the bolt face.
 
One would think that the cocking piece on the trigger sear would provide some "pull back" to get a valid reading on the jiffy marker on the rear of bolt lugs - to see how well they seat to their pads in the receiver. But I have no experience with Remington 700 - so might be different??

With no markings on rear of bolt lugs - is as if the firing cartridge grabbed completely on the chamber walls, and then put no rearward pressure on the bolt lugs - not sure if that is possible? For accuracy issues - is possible that something amiss on that muzzle crown? If you have seen the odd pit on the rifling - maybe that muzzle crown needs a good look? - should be "sharp" edge all the way around - want that crown to release bullet at same time, around entire circumference?

I do not know if it helps, but on M96 and M98 Mausers, I have removed the firing pin / cocking piece - just the bare bolt body. It appears on those there is a smidgeon of clearance ahead of the bolt nose. So, I jiffy marker the rear of bolt lugs and slid bolt in - pushing forward until it hits something, then close bolt while still pushing forward. Then pull back on bolt handle and work it up and down, maybe 45 degrees - I am presuming that pulling back on handle makes the lugs tight to their seat. Then push forward again and open the bolt and remove it - I do not recall not seeing wear marks on the lugs - sometimes not even close to equal - but was always "something" showing, not "nothing".

Because I often play with random receiver, random bolt and random barrel, I often get to check that lug fit to a receiver without a barrel in place - that lets me put thumb pressure on the bolt face from the front. More than once discovered "lug set back" - distinct hollow in the receiver seat, where the bolt is fully closed. Can see how the jiffy marker rubs off. One would think with original bolt to that receiver, a slight amount of "set back" would assure full lug bearing, but I seldom have luxury of an original matching bolt. So the jiffy marker on the bolt lug, will only tell you stuff, if the seat faces in the receiver are dead flat - can not work well if there is "set-back" in there? But almost always get at least some jiffy marker rubbed off the bolt lugs.
 
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Here’s some pictures of the bolt. All of the usual accuracy suspects have been checked. Bedded, crown, action screw tension, concentricity of ammo, etc. Not my first range rodeo, I can take almost any other gun to the range at the same time and produce it’s expected results. Just can’t figure this one out and wondering if it’s a bolt or action issue. The flyers are just turning sub .5 moa groups into .75-1.0” groups and I guess I’m just expecting better and more consistent.
 
If you want to check lug contact, one of the better ways is to put a layer of masking tape on the back of a piece of brass to provide rearward pressure. Allowing the striker to provide rearward pressure would work except that the sear tends to deflect the rear of the bolt upward and take the top lug out of contact.
As far as the accuracy, or lack thereof. of your rifle is concerned, I can't comment specifically since I can't see it. I don't know if it is properly bedded, chambered or crowned. I don't know whether or not your scope is a turkey or your ammunition is straight and consistent. In other wards, as I have occasionally been told, I don't know squat!
 
Having now looked at the pictures and re-read your description of the flyers etc., I'm leaning towards a scope or mount problem with the potential for a barrel fouling. Are your flyers vertical (high, low) or around the clock?
 
At this stage I would not worry about the lugs...

First of all do you have a rifle you can shoot consistently under 1/2 inch?

If you have not had the action bedded and the barrel floated and recrowned and the trigger set up about 2 pounds - have that done.

Then clean the barrel and try a match bullet in the 50 to 53 grain range with about 24 grains of BL-C2... I always used Rem 7 1/2 primers.
 
Thanks for all the advice. I’ll try some of the suggestions. Scope and mounts have been checked and changed to verify. Brand new KS barrel 1:14 twist, match chamber done by my regular smith from which I have a couple in the safe that produce the desired accuracy of .5moa or less of which I’m quite capable of duplicating. I’ll try the tape, forgot about that. Maybe a different scope and certainly some BLC-2 with some Hornady 52gr BTHP match and 71/2s. The flyers can be in any direction but more often to the right. Trigger is right at 2lbs. Wish me luck:)
 
Peecos not much to offer other than if you don’t have BLC2 or R 7 1/2 primers I have both you can have to try out. I have 52 BTHP as well but I think you still have some. Good luck.
 
Since you have the Sharpie handy, mark up the end of your front bedding screw and the tighten it up. Then remove the front screw and make sure the marker hasn't rubbed off. Front bedding screw might be bottomed out without you knowing.
 
Peecos;[URL="tel:19029561" said:
19029561[/URL]]I have a 1977 issue Remington 700 BDL short action that’s giving me a headache. Purchased used on the EE here it’s in excellent condition but just would not provide satisfactory accuracy in the shoots anything into tiny bugholes .222 Remington. A bore scope showed a few small pits on the edges of the rifling but nothing major. Lots of different bullets, powder and primer combinations tried and not what I was looking for. It’s MOA so maybe my expectations are to high. Groups of 5 round always have one or two flyers or two separate groups. My desire for an accurate .222 was high so on goes a new custom barrel! Well it’s doing the exact same thing but I’m still working on different powder/primer combinations at the moment. Yesterday it occurred to me to check the bolt lugs for even wear and there is none! It’s 45 years old and shows typical wear on other friction points on the bolt but not on the rear of the lugs. If I use a sharpie on the lugs to check for contact should I remove the firing pin assembly? Should I have a new or fired in this gun piece of brass in the chamber? I’ll get some pictures to post for visuals a little later. Cheers

you dont need to remove the striker BUT try marking the back of the lugs then holding the trigger back as you close and drop the bolt handle down so the cocking piece/striker goes forward and the firing pin spring tension is release. Then while pulling back on the bolt handle rotate the bolt handle about 30-40 degrees and have a look if there is any evidence of your marker being removed from both lugs-if the marker is being rubbed off your problem maybe that the bolt race is a sloppy fit. I believe there is a fix for that as one of the contributing gunsmiths on here can advise
 
It is better to machine the lugs and the corresponding recess in the action than to lap lugs... I have seen some very tapered locking lugs from too much lapping...
 
Had it to the range yesterday to verify a few things and try some different loads. Complete scope/mount change to compare to previous groups, no changes. Removed the sling studs to make sure they weren’t hitting the front or rear bags. No luck with the Hornady 53gr hp match BL-C2 / 71/2 combos. 25.0 grs was just under 1moa, I’ll do some more playing with it later. Some success with N130 and 50gr vmax and CCI 450. Consistent velocities, round grouping and more typical patterns through the loads. A couple with the kind of accuracy I’m looking for so we’ll see if it can repeat. I guess it’s just fussy and so am I. Mostly I was curious about the lack of wear marks on the back of the bolt lugs but maybe that means it fits perfect? Anyway, thanks for the tips and advice. Happy shooting:)
 
That caliber offers a fraction of the bolt thrust compared to a typical 30 cal. So the action/lug stresses are fractioned accordingly. This is probably why you dont see engagement marks...
 
What twist rate does your barrel have??

Some 1-14 twist barrels will only stabilize bullets of 55 grains with flat bases.

If this is the case, you may have to load very close to maximum pressures to attain enough velocity to stabilize your bullets.

If you don't want to do that my suggestion is that you use bullets for which that cartridge was originally intended to use, which were in the 45-50 grain range.

The last Remington 700 I had, chambered for the 222, had a 1-14 twist rate. It never shot 55 grain bullets of any shape into groups that were less than an inch.

It had an excellent 6X fixed power Burris scope, with AO ring on the front.

The scope was almost perfect for parallax if I did my part to adjust it properly.

Even pushing the velocities as fast as I felt comfortable with, groups just wouldn't tighten up to my satisfaction

The rifle had a Varmint contour barrel, mounted at the Remington Custom Shop.

I called the good people at Remington and they put me through to the fellow in charge of their Custom Shop.

He was very good at listening to my issues with accuracy and then he told me, "some rifles just won't give match or varmint accuracy with the 55 grain bullets" Then he suggested I go to 45 grain bullets and stick with flat bases.

There was more, but that was the main gist of his advice. HE WAS RIGHT. That rifle shot 45 grain, flat base bullets, made by Sierra into very consistent sub centimeter groups, as long as I did my part.

It was also very consistent with 40 grain and not quite as good with 50 grain bullets.

I just couldn't get it to shoot any of the spitzer boat tail type bullets in any weight.

I'm willing to bet you have a bullet type issue, rather than anything mechanical.

As for bolt thrust, that is determined by the pressures generated. IMHO, the bolt thrust generated by your rifle is very close to that of the 223rem
 
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Twist is 1-14 and yes it doesn’t seem to like anything over 50gr. I agree about the flat base bullets but currently I can’t find any in the 40-50gr range. 40gr vmax shoot okay I just wish they came in a flat base as their shank is very short. Speed definitely helps as best groups are always at or near max.
 
The 222 chamber should have a near zero freebore due to the long neck. If two barrels are acting the same I would think it’s your shooting rather then the equipment. Try different holds. Squeeze the butt in your rear bag, or not. Hold the forearm or free recoil.
 
OP, you don't mention your scope.

Does it have AO???

Most fixed AO scopes parallax is set for 125-150 meters.

I'm still leaning towards your selection of bullets.

Your action is very strong and depending on throat depth, you should be able to seat your bullets so they are touching the leade

I had to do that with my rifle.

As for buckmaster's info on the freebore, my factory barrel had enough freebore that I could just barely seat the 40gr bullets out far enough to touch the lands, so freebore was minimal.

That rifle I had wouldn't shoot full length resized cases well, neck and partial resized did very well, once I established it preferred 40-45 grain bullets

My accuracy load for both those weights was 28.5 grains of H335 over CCI small rifle, magnum primers.
 
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