B78 needs work

[Catch]

My B78 in 30-06 is shooting poorly and I suspect the bedding. I have tried enough different loading combinations to have seen some difference, but it remains consistently inconsistent. I have even tried the small slug between the barrel and the hanger threaded as to provide adjustable pressure between the hanger and the barrel with the same inconsistent results. My last effort was a shim between the fore arm and the hanger to keep the fore arm farther from the barrel. Same results.
I would like to hear your ideas on this problem and any suggestions that I may try, as I am considering hanging this beautiful rifle over the fireplace.............
It has a 26 in. barrel, and I have even considered cutting it to 24 and re-crowning although I hate doing things that I cannot return to original.....
Help..........[smilie=b: Catch

[Tatume]

On my oldest 1885, also a 30-06, I found that the stock had loosened slightly. Tightening cured its woes.

[Catch]

Do you mean the buttstock?

[Tatume]

Do you mean the buttstock?

Yes .

[gnoahhh]

Is the rear of the fore end bearing against the front of the receiver? You might try separating the two by a few thousandths of an inch- not enough to be noticeable. It's one trick I've found to work on several single shot designs. I suppose it furthers the thought of isolating the fore end as much as possible from the dynamics of the receiver/barrel dance that occurs on discharge.

[montana_charlie]

My B78 in 30-06 is shooting poorly and I suspect the bedding.

I have even tried the small slug between the barrel and the hanger threaded as to provide adjustable pressure between the hanger and the barrel with the same inconsistent results.

My last effort was a shim between the fore arm and the hanger to keep the fore arm farther from the barrel. Same results.
Then, you have proven that barrel bedding is not the problem ...

CM

[flounderman]

one article on the ruger no 1 the guy glassed the fore end to the barrel and it shot good until it broke the bond. what does the muzzle end look like? seen an article on using whiteout around the crown and if it blackens unevenly, the crown is suspect. what are you shooting in it and how clean is the barrel regarding copper fouling or leading? what weight bullet, what twist? try a lighter bullet. partial neck size, seat bullet to touch rifling. have you checked the mount screws and tried a different scope? trying a different scope and making sure the mount screws are tight would be one of the first things I would look at. cutting the barrel would be the last.

[pietro]

I once had an octagon-barreled (26") .30-06 B-78 (in 1975), that shot like a house afire - BUT, I had to keep it's bore scrubbed out religiously. (I later also used an Outers Foul Out)

If ANY jacket/copper fouling got in there, the accuracy went South until I cleaned it.

OTOH, I also had a 6mm Rem B-78 with a 26" RB that would shoot great, even if I left it looking like the inside of a sewer pipe - go figure........

.

[bigted]

i also have found that the bore cleaning is paramount to accuracy on some rifles especially. my new found cure for a barrel that seems to foul especially easy is thusly...

run about 100 paperpatch boolits thru it AFTER it is absolutly clean of jacketed or lead fouling. this is super important with the barrel to be completely clean before using the paperpatched boolits. those papered boolits will scour the bore to a sheen that is only atainable with a bunch of elbo greese when hand polishing the bore.

the reasson this is sometimes a problem...[no matter what some say]...is improper breakin of the barrel. here is the "teds theory on breakin"...

when new a production barrel is rough and has tooling marks still on the interior of the barrel. sometimes the stamping is done AFTER the bore is cut with rifling and hence is tight in those areas so...this is also necessary for a proper breakin of these rough barrels...

i use 2 box's of factory jacketed shells...does two things...gives me a good break-in AND gives me 40 cases that are chamber formed to your chamber...

take the first box of 20 and shoot 1 round then do a thouro clean and get all the jacket wash out of the bore...after a complete cool down and cleaning then swab the bore dry and shoot another round...do the same for every round for the first box of 20 rounds...this will take patience and perserverance and most of a morning to do.

what is happening is that all the rough "hairs" of the fresh milled steel are being slowly "ironed" to lay down or break off leaving the bore fresh and shiney and most importantly SMOOTH. there is nothing left for the jacketed wash or lead or powder fouling to get stuck in.

now the second box is fired in twoe's for the entire box...do the same thing as the first box except shoot 2 rounds thru the barrel in a row then do the same cleaning as with the single shots on the first box of shells. after having this treatment with a new barrel...then the barrel is "ironed " and smooth so that the cleaning will be the easyest possible for the rest of the rifles life...or the barrels life to be exact.

if you have a barrel that has not been ironed in a like fasion then it will be a fouler for the rest of its life...sometimes the bore has jacket wash and powder fouling UNDER the hair of the barrel steel inside and will be very very hard or impossible to remove later on in its life.

it is still advisable to use a very strong amonia cleaner to try to get your bore as clean as possible and then do the breakin as described to try to save the barrel from being a fouler from now on.

good luck on your browning...those are ussually a very good shooter and very strong...2nd only to the ruger action and only then becouse of the firing pin hole being bored straight thru instead of angled down inside the action in the per chance of a ruptured primer.

[texasmac]

Bigted,

I'm not trying to "hijack" this thread but felt I had to take exception to your comment about the firing pin in the Browning.

The Miroku Browning & Winchester firing pin design is based on the Mann-Niedner type, which, along with the breechblock design, eliminates any possibility of high-pressure blowback from a ruptured primer. The firing pin has a large diameter shoulder which prevents it from being blown back through the smaller diameter hole in the rear of the breechblock. In the event of a ruptured primer, the breechblock has a large vent under the firing pin to divert escaping gases down into the action, away from the shooters face.

By the way, just to complete the details of the design, the firing pin is retracted by a coil spring and held in place by a large bushing, which is threaded into the front of the breechblock. A retainer pin through the breechblock and along one edge of the bushing prevents the bushing from turning and working loose.

Wayne

[1874Sharps]

Like others here, I have found that my Browning HW 30-06 is sensitive to copper fouling and its effects on accuracy. What fun, great rifles they are! I can attest to what BigTed says about the beneficial effects of paper patch boolits on removing toolmarks and imparting a mirror smooth surface.

Catch,

In troubleshooting I have found it is always best to start with the simple and most likely causes of the problem and work from there. It could be that a good scrubbing of the ol' bore (or Outer's Foul Out electroplating bore cleaner) might do the trick, or a buttstock retightening. For me, when accuracy degraded on mine, a good cleaning did the trick.

[bigted]

texasmac...thanks for the update on the pin hole on these fine rifles. i merely meant that compared to the ruger...the hiwall's have the pin hole...-shouldered even tho...bored straight thru the block and pointed at the shooters face. the likely hood of either rifle blowing into your face in a catastrofic failure is a rare happening but in that case i think id rather have the ruger then the hiwall.

not argueing as you know tons more about this new design then myself...just pointing out the obvious diff in where the hole is bored is all

again thanks for the added info and im definetly a fan of these rifles...i have three that i shoot all the time and 1 ruger that mostly just sets ther and looks lonely.

[texasmac]

Bigted,

An interesting experiment would be to somehow test the pressure capabilities of the Ruger versus the Browning/Win. High Wall design until one failed.

Back in the mid 1990's When Browning was considering the Badger barrels for the BPCR high-wall model (introduced in 1996), using smokeless powder loads, they increased the chamber pressures to a level sufficient to liquefy the brass and drive it into the extractor slot. The brass was cleaned out and the testing continued without failure. Based on the test results, “calculated” failure pressures were well above any range expected to be reached with commercial smokeless ammo.

Maybe we can get the TV show MythBusters to tackle the task. That would be an interesting episode.

Wayne

[bigted]

i agree

[Olevern]

I once had a single shot (Ruger #1 in .220 swift) that would shoot with most benchrest rifles if benchrest loading techniques were used AND I kept the buttstock screw torqued to a specific value. This value was found thru long experimentation and had to be checked before each bench session because it varied as the stock picked up moisture or dried with normal variations in humidity. Took more than a few dollars from fellows with $2,800.00 rifles topped by $1,500 scopes with that old heavy barrel (factory) .220 and they walked away shakin their heads. Used a stock Leupold 6.5X20 on top in lapped rings.

[EDG]

The amount of metal under load in the side walls of these two actions is enormous compared to the bolt actions considered by handloaders to be the strongest of actions. The load paths are also short so the tendency of the action to stretch is also minimized. If you look at the breeching mechanism of many artillery pieces you will find the same basic design.
EDG


Bigted,

An interesting experiment would be to somehow test the pressure capabilities of the Ruger versus the Browning/Win. High Wall design until one failed.

Back in the mid 1990's When Browning was considering the Badger barrels for the BPCR high-wall model (introduced in 1996), using smokeless powder loads, they increased the chamber pressures to a level sufficient to liquefy the brass and drive it into the extractor slot. The brass was cleaned out and the testing continued without failure. Based on the test results, “calculated” failure pressures were well above any range expected to be reached with commercial smokeless ammo.

Maybe we can get the TV show MythBusters to tackle the task. That would be an interesting episode.

Wayne

[Catch]

Well I wanted to report back on my progress so far: Thanks so much for all the good ideas.
The two things that seemed to fix the problem were: tightening the buttstock was probably the most important part as the groups were cut by almost two thirds. Secondly I tried removing the forearm completely and shot the thing resting on the hanger. This really improved things and I was getting one to one and one quarter inch groups. Two questions: How do I fix the forearm to make the thing free float completely? My first try will be to shim the bottom of the forearm to keep the barrel from touching it anywhere. Secondly I am afraid to overtighten the butt stock. Does anyone have an idea of the proper torque here? After researching the trigger, it has 4 adjustments and I am still somewhat confused where to start here as my research seems to show that this particular model even confuses the pro gunsmiths.......I also have a book that the author suggests some of the black silicon sealer that comes in a tube between the barrel and the forearm and hanger. I'm still thinking on this one. But I am having a hell of a good time, and thats the best part............Thanks again.

[bigted]

you mentioned the easyiest way to float the forarm...shim it till it no longer contacts the barrel anyplace. the other and probably best is to enlarge the barrel channel so the same thing is aquired...no contact with the barrel...id hesitate to put any gue in there. there is usually no shortcuts to good work on your rifle.

the buttstock will have to have somebody smarter then myself to tell the foot pounds or inch pounds...id be interested in this number myself tho.

[gnoahhh]

I should think that tightening the stock bolt with a torque wrench until optimal accuracy is achieved and then making a note of the wrench setting for future use would be one way to find out. Beware though that all torque wrenches aren't the same. You will get different readings from wrenches of the same batch. The markings on the barrel are an approximation at best. Take it from someone who used to work in a factory that manufactured torque wrenches. Each wrench had to pass a QC test, but there were pretty broad parameters for pass/fail. (We made wrenches sold under a myriad of popular labels.) Determine what's right in your circumstance and stick with the same wrench for future re-torquing.

[montana_charlie]

The amount of metal under load in the side walls of these two actions is enormous compared to the bolt actions considered by handloaders to be the strongest of actions. The load paths are also short so the tendency of the action to stretch is also minimized. If you look at the breeching mechanism of many artillery pieces you will find the same basic design.
EDG
Bigted,

An interesting experiment would be to somehow test the pressure capabilities of the Ruger versus the Browning/Win. High Wall design until one failed.

Back in the mid 1990's When Browning was considering the Badger barrels for the BPCR high-wall model (introduced in 1996), using smokeless powder loads, they increased the chamber pressures to a level sufficient to liquefy the brass and drive it into the extractor slot. The brass was cleaned out and the testing continued without failure. Based on the test results, “calculated” failure pressures were well above any range expected to be reached with commercial smokeless ammo.

Maybe we can get the TV show MythBusters to tackle the task. That would be an interesting episode.

Wayne

You might be interested in this information from Pedersoli's Dick Trenk which details a similar test on a falling block action.

The regular Pedersoli 1874 Sharps models copy the original Sharps dimensions except we have made the side plates .050" thicker than the originals (which Shiloh copies more closely). Because Pedersoli knew some shooters would likely use smokeless powder with dangerous pressures, the decision to make the action more husky was done to safeguard against rupturing the breech block side plate grooves, which now are set deeper and stronger in the Pedersoli models. Many years ago a gun was sacrificed at the proof house to see what pressure could cause problems.
At 72,500 psi chamber pressure we found .003" setback on the breech block but no chamber or barrel harm and the barrel passed proof test gauges OK. Such a pressure was obtained using a machined steel ctg. case in 45-70 size which had a small primer pocket., plus using 3x500 gr bullets, plus full case of bullseye powder.

[bigted]

by gosh...ill have to look at my pedrosoli/uberti sharps a little differently now...72,500 psi???thats insane and then only .003 setback of the breech black??? what a mule of an action...glad i have 1.