Rifle Woes

Z

Zebra13

Member
Gents,

I just completed a build for a friend, and the confounded thing will not shoot! While I haven't built a lot of rifles, the ones prior to this have all shot well right out of the gate. I have worked with numerous sick rifles and with the exception of one, have made them all shoot better. But this one has got me scratching my bald-ass head.

I keep getting weird, 3&2, or 4&1 groups, the separation between the two is always vertical, and the first shot is usually out and off call (hot or cold barrel). I have yet to get a "flat" group. Typically, this points to a bedding issue, but the bedding on this rifle, checked using the dial indicator method, shows about a half-thou of movement, if that. That's pretty good...and quite remarkable given all the garbage that is on the bottom of a SS 700 action these days. I've seen rifles with far more movement shoot far better than this one. I thought I had it licked when I discovered the stock was contacting the barrel during recoil. I relieved the barrel channel a bit, Prussian blued the barrel, put it back together and shot it. No more barrel/stock contact, but the same group pattern remained (the barrel is completely free-floated). Different torque settings for the action screws? Nope...not it. I tried another stock, this one was not glass bedded (aluminum bedding block), and when checked with the indicator, it showed about .003-.004 movement. What the hell...I took it out and shot it. Same type of groups. I have tried 3 different scopes, and a different set of rings. No dice.

To rule out operator error, I shot my personal .308 during one of the range sessions, and had no problems shooting respectable groups.

Ammo was factory 308 Hornady TAP 168 grain, and Federal Gold Medal Match, 168 grain BTHP, both of which, especially the Hornady, have shot well in every prior 308 I've ever messed with.

The rifle was chambered in my Emco Super 11 lathe, using the through the headstock method with wire rings betwixt the chuck jaws and barrel. The outboard end spider has swivel-tip screws to hold the barrel. I indicated directly of the lands with an Interapid with a long stylus to around a tenth, pre-bored, and chambered using Vipers Venom. After each operation...threading, chambering, etc., I re-checked the both ends of the barrel with the indicator (thank you, Jackie). Nothing moved. When done, the chamber had about .00015 of run out. Reamer holder was a Bald Eagle using the pusher method. Visual inspection with my borescope checked-out, everything looking concentric and true. The throat was given a brief short-stroking with a bit of lapping compound on a patch to knock off the sharp edges and burrs caused by the reamer. The crown was my typical recessed, cut 90 degrees to the bore, with a 45 degree chamfer cut on the very end, and checked with a Q-tip. Crowning was done with a crown-specific, honed, HSS tool that I have used in the past, and was put at a tight spot felt when I slugged the barrel.

The screws don't touch the insides of the pillars, the scope base screws don't touch the barrel tenon. Firing pin fall is around .260, with about .030 sear handoff. Firing pin protrusion is .054. Firing spring has not been checked. Rings and bases are torqued to specs. The only thing that I can think of that I haven't done is bed the bases, and lap the rings, both of which I intend to do. I'd be surprised if this was the culprit, though, as I have seen many a rifle (field rifle) shoot well without these steps being done, but you never know. Clearances between bolt and barrel are good. I've checked everything I can think of to check...twice. This rifle is handing me my arse. I miss my longbows...

Having never had a bad/problem barrel, when do you start looking at it as a suspect?

The particulars for the rifle are as follows:

Remington 700 SS (brand new), trued, PT&G bolt handle welded-up by Dan of Accu-Tig
Krieger 4 groove, 1-10, twist, 30 caliber, Remington Sendero contour
Trigger Tech trigger
Mc3 stock, bedded in Marine Tex
Chambered in .308 Winchester with a brand new PT&G SAMMI spec, live pilot reamer.
Warne picatinny bases, Seekins rings.

So...what say you, gentlemen? Where do I go from here? What have I missed? What do you recommend I do next? I've tried to cover all the particulars and my doings, to help give you guys the total picture, but may have forgot something. If I have, please ask.

SOS

Justin
 
Vertical often shows ignition problems if shooting off known good rests and and known good components. Look for burrs on firing pin or roughness in the bore of the bolt or an oversized firing pin spring. This can all give inconsistent ignition. Also check your trigger and bolt to make sure there is no interference with the release of the firing pin.
 
Not knowing anything about the you and the rifle this is what I would do if you walked into my shop. First I'd make sure the bolt handle wasn't touching the stock. Next check and make sure the bolt nose has plenty of clearance in the CB. Dry fire it and listen to the ignition system. Clear and crisp or muted and dull. There is a difference in performance between the two. Check the amount of firing pin fall. Then make sure there is plenty of clearance for the barrel.
 
Two questions: How big are the groups? When you trued the action, did you re-cut the threads?
 
Not knowing how much you might have cut off the muzzle end. I would go ahead and check if it was enough using guage pins. Something similar once happened to myself and it ended up still being a bit oversized at the muzzle / belled.
 
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John VM said:
Vertical often shows ignition problems if shooting off known good rests and and known good components. Look for burrs on firing pin or roughness in the bore of the bolt or an oversized firing pin spring. This can all give inconsistent ignition. Also check your trigger and bolt to make sure there is no interference with the release of the firing pin.
Click to expand...

What John said with one addition. I've had vertical issue from nothing more than a weak firing pin spring.
 
I thought of a couple more things. Check the length of the front guard screw and the rear scope base screw. They might be touching the bolt lugs. Stranger things have happened.
 
Eurika or not

You seemed to have checked almost everything. There are a couple of things you have skipped or didn't mention. One is lug contact and the other is the firing pin spring. Do double check the crown. Once those check out you just may have a bad barrel. This last one is an expensive fix. There are a couple of secrets to try when all else fails. The first one involves removing the barrel and pissing through it. The second involves the occult such as Voodoo ceremonies, magic crystals or curse removal. Tim
 
SGS said:
Two questions: How big are the groups? When you trued the action, did you re-cut the threads?
Click to expand...

I ask about the threads because although most of the new Rem actions are straighter than the old ones, there are exceptions. I have seen threads so badly out of parallel to the receiver bolt centerline as to prevent the barrel from tightening up fully against the lug even showing a barely perceptible gap on one side. Closely fitted threads make this condition much worse. Also likely to have bolt nose contact in the counterbore even with what seems to be plenty of clearance.

This condition will make the best barrel in the world shoot badly.
Putting some up pressure on the barrel with cardboard shims cam help to pinpoint this issue.
 
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Gents,

My apologies for not responding sooner, but life got busy there for a spell, to include, as I am now North of the big 5-O, a certain medical procedure akin to the borescoping of a barrel. With the exception of a couple of polyps, and a small colony of gerbils, my 1 in None twist looked just fine.

And thank you to all for taking the time to respond to my post and give suggestions on how to remedy my sick rifle.

I carefully read all the advice and suggestions on things to check, likely accuracy-robbing culprits, etc., and started with the one bit of advice that made the most sense to me and would, in my opinion, likely clear-up my accuracy issues. I took the rifle to the range, and per Dr. Tim's advice, took a leak down the barrel. After spending the night in jail on an indecent exposure charge, me and my newly installed ankle monitor repaired back to the shop to examine some other options...

As the bedding checked-out OK, all of the suggestions to look at the ignition system resonated in my thick skull, especially after having read James Kelbly's thread in the F-Class forum on what not to do to Kelbly actions to improve accuracy. Following the advice of Dave Tooley, I paid special attention to the sound of the firing pin whilst dry firing, and it was a wonky thud, and not a crisp click. When I put a different bolt in the gun and dry fired, I got a nice, sharp, click. OK...now why a thud and not a click? JohnVM cited likely ignition problems and suggested checking for burrs on the firing pin and inside the bolt bore. So I stripped the bolt, and with the naked eye and a flashlight, could see a BIG ASS chip/burr at the bottom, and a couple other spots of bother. My borescope confirmed the sh!t show that was occurring inside of my bolt. I took a photo of this through my borescope, and while not Ansel Adams quality, the chip, as it turned out to be, can be clearly seen at the 11 o'clock position. There was also a bit of sh!t at the 12 o'clock position in the counterbore (the marking at the 7 o'clock position in the counterbore is a tool mark, the one next to it appears to be braze/solder). I chucked-up a cleaning rod with a 44 caliber bronze brush on it in my cordless and gave the bolt innards a good scrubbing, followed by a flushing. A check with the borescope determined the offending chips were now gone. Upon re-assembly, I was rewarded with nice, crisp clicks when dry firing, and an additional .003 of firing pin protrusion. Who would've thought there would be a metal chip inside the bolt?! Back to the range...

Conditions sucked, with switchy winds of 10-20 mph. Despite this, shooting without flags and off of a bipod, my first group was a 4&1 that measured under a half inch. The remaining groups were all 4&1 weather reports, with the 1 turning a sub half-inch or so group into a .7 or so, but the vertical, 3&2 nonsense was gone. The groups were flatter. A local benchrest competitor of good repute was at the range at the same time, and he was impressed with the groups, all things considered.

I know...get some flags, stupid!

She is really trying to shoot, but those damn 4&1's!

I guess the conditions, in theory, could have been responsible for the 1 shot being out everytime, but me thinks not. I have another theory...

I think I may still have a bit of an ignition problem, and here's why: The firing pin on this rifle is fluted (from the factory) and weighs about 475 grains. Checking a couple of non-fluted, factory firing pins showed them to weigh about 650 grains. Further, the firing pin spring was about .007 smaller in diameter than the other firing pin springs I had on hand. Having read James Kelbly's aforementioned thread, and a post by Greg Walley on ignition testing he did, plus their conversations with Mike Walker, who designed the 700 and spent a bunch of Remington's time and money coming up with the correct combination to ensure reliable ignition, I wonder if Remington's use of a lighter firing pin (and possibly spring...I don't have a way to check it) is causing my consistent, one shot flyer? I know Jackie has fixed a rifle or two by increasing the weight of the firing pin spring...more energy to the primer. I wonder if this is the culprit? And I wonder why Remington changed it at all?

My theory would be easy to check with a firing pin swap, and I just may do that.

What say you?

Thanks,
Justin
 

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Try it with flags and different ammo. Factory match ammo has to match the rifle or it won’t work well Barrels and bullets have to agree with each other. 4 and ones are notoriously shooter error and you could be wishing it in but getting sloppy and not paying attention to execution.
 
Ol' Beggs again.

Justin, I've been following your thread with interest as I have been there. I think I can help.
I have been a short-range benchrester for over thirty years with a reasonable degree of success.
What you are experiencing with your Rem 700 308 is very common with accuracy minded shooters that are expecting too much from their equipment. If you are getting 3 in 2 out, and 4 in one out with an occasional .7 moa flier, you may not realize it but you are getting excellent accuracy with your equipment. In order to improve on that, you will have to move on up to all out benchrest equipment to include;

1. Custom built benchrest rifle chambered in a BR cartridge.
2. Benchrest quality front rest and rear bag.
3. 36 or greater power target scope with appropriate reticle. ( I prefer 1/16 dot)
4. Benchrest quality and proven custom made bullets. (Bart's are hard to beat; so are Berger)
5. And the list goes on and on forever,,,

What you need now is a very experienced and knowledgeable mentor and CA has quite a number of those. Take a drive over to Phoenix and attend one of their BR matches at Ben Avery. Get acquainted with them and ask a lot of questions. They will be glad to help you.

Move on up to short range BR. You won't believe what you will learn in the first year. Keep and enjoy that fine Rem 700 sporting rifle but in order to obtain the accuracy you really want; take up real BR.

Sincerely,

Gene Beggs
Odessa, TX 79762
 
Some have missed that Justin has been around this game for several years. He does know how to turn on a lathe. He will appreciate any help offered.
 
Butch Lambert said:
Some have missed that Justin has been around this game for several years. He does know how to turn on a lathe. He will appreciate any help offered.
Click to expand...


Butch, thanks for reminding me that Justin is not a newcomer to shooting and machine work. I hope he did not think I was putting him down by suggesting that he accept his 308 sporting rifle's accuracy for what it was designed for. If one has not been involved in extreme accuracy in the past few years, there is a whole new world of discoveries to be made. I have to remember that there are other forms of shooting and levels of accuracy besides benchrest.

Thanks for the input.

Gene Beggs
 
Gene Beggs said:
Butch, thanks for reminding me that Justin is not a newcomer to shooting and machine work. I hope he did not think I was putting him down by suggesting that he accept his 308 sporting rifle's accuracy for what it was designed for. If one has not been involved in extreme accuracy in the past few years, there is a whole new world of discoveries to be made. I have to remember that there are other forms of shooting and levels of accuracy besides benchrest.

Thanks for the input.

Gene Beggs
Click to expand...

Gene, You know I wouldn't put you down. Your knowledge has helped a lot of folks!
 
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