RBriscoe wrote:Yes, Tony, TC/U chambers were all over the place, but were not a problem once you fit (fire formed) the brass to the chamber as you did. It does illustrate the beauty of having your own reamer, ground to fit the brass and dies in the first place.

Merry Christmas and a Happy New Year to you, my friend!

Rick

Same to you Rick

In keeping with Mr Briscoe's analysis one should always fireform new brass. Seat the bullet out until it engages the lands and forces the case head and primer tight against the bolt face. Then and only then can you be sure that each round thereafter is precise to that chamber. Neck size only until things get sticky and then shoulder bump a couple of thousands. sadly Rugers (and weatherbys and some new Rems) have real long throats making the "seating out" problematic. Low pressure pushes primers out because there isn't enough umph to push the case back fast enough. Too rough a chamber does the same. But remember..Ruger's have long throats...thus screwing up the pressure curve (it drops off more quickly)

Most of the time and especially when dealing with club "experts" the easiest answer is the most likely, your expert probably loaded the ammunition himself with new brass {that would explain it's factory appearance and small dimension} and loaded a very light starting load and seated the bullets to minimum length. The firing pin pushes the case forward in the chamber before ignition but there isn't enough pressure from a light load to expand the case back against the bolt face. However there is enough pressure to push the primer out of the pocket until it hits the boltface. Most of these types never admit any errors on there part so he'll blame it on the gun if he even recognizes the problem.
Kb

In all my years of shooting and the many rifles that have come and gone through my hands I never had one that left backed out primers to any great degree. Well, except for my Marlin .30-30 lever gun and my trusty Remington 788. The rear lock up design on the 788 bolt allows some flex upon firing which always leaves the primer backed out from .012 to .016 regardless of what the load was. Light, medium or heavy leaves the same condition every time. I full length the size the case every time, without pushing the shoulder back, to avoid putting excessive closing pressure on the weakly braised on bolt handle. I have had this gun for 32 years and it is on its second barrel. It was a .308 and still had the same primer back out issue. It is now a 7-08. This flexing condition along with full length sizing leads to poor brass life. The best I can get is about 5 to 7 times before evidence of head separation occurs. Neck sizing nets me one or two more firings but puts more closing stress on the bolt handle. These handles are a weak point in this model. Short brass life is is no big deal to me as this rifle is a real accurate one as most are.

I had it out with me yesterday along with a few others for some practice. I took some photos of the brass...just for grins.





40 of the 50 rounds fired from the rifle showed some degree of head failure. These were formed from new W-W .243 brass. They only lasted 5 firings. The load was 40.0 grs. RL-15 pushing a 130 gr. Speer flat base spitzer and a CCI 200 primer.





Mr.Briscoe, after reading your post about up to .060 primer back out I punched one out to .055 backed out. That sir is a heck of a lot of movement. It seems that a condition that allowed this to happen would certainly cause a broken off head every trigger pull.

Yes when he described the gun in the initial comment on this thread he said "Ruger mark 1" does he refer to the #1 falling block or a front locking bolt gun like the Ruger 77? Not much flex in the 77 and #1's usually exhibit extraction problems long before any other pressure sign, causing the careful shooter to back off the load.
Bob, most of the time that I see backed out primers is when intentionally loading reduced loads{1150fps} with IMR4759 or cast bullet loads and with IMR 4064 trying to hit that sweet spot at 1800fps.
Kb

Bob Mc Alice wrote:
Mr.Brisco, after reading your post about up to .060 primer back out I punched one out to .055 backed out. That sir is a heck of a lot of movement. It seems that a condition that allowed this to happen would certainly cause a broken off head every trigger pull.

Yea, Bob, that's a heck of a lot. The point was not the amount in that particular case (and it was the most extreme example I have encountered), but that new brass and ammo are frequently a lot smaller than many people realize and that should be taken into account when either chambering a rifle or fire forming/fitting brass to a chamber.

Have you run a dental pick or something inside you cases to see if you can feel the start of the case head separation? Those 788s are shooters though, and have a fast lock time as well. The Win 243 cases are generally good brass and sure cost a lot less than that stuff from Finland.

Regards,

Rick

It was a Ruger 77 Mark I, Interesting enough about the 788, when they first came out I think they sold for like $90.00 and they shot better than most of the 700's. I was reading an article one time about longer barrels creating more velocity than shorter barrels, the writer claimed that it just wasn't so in a .308 Win. At that time I had 3, a 700V with a 24 in. barrel and a 788 with a 20 in barrel and a 70 with a 22 in barrel, for grins I cronoed the three with if memory serves me with a 168 and about 40grs of IMR 4064 or 4895, but they all chronoed pretty much the same. When I first started shooting silhouette it was with the 788, very fast lock time, very poor trigger, I think Timney is making a trigger for them now.

Timney does make a trigger for the 788 that, with slight modification (shortening the sear I believe they said), also fits a 541.

Rick, the bent paper clip feel method easily detects the thin spot inside the case.

I worked my magic on the stock trigger long ago. Got it down to a 3lb crisp reliable break. No way would I put a $125.00 trigger in a $125.00 gun....no sir.

I just got home from the range again. Finished off the remaining 50 rds. of that 130 Speer load along with 150 other assorted rounds in four different guns. Was cold at 7:30am but warmed to 55 by noon and was mostly calm all day. I was experiencing some light primer strikes (no boom) this spring with the 788. The original 20 lb. spring was getting tired. I installed a Wolff heavy duty 25 lb. one in April and no problems since. That's all the trouble I've had with this rifle. The best $125.00 rifle I ever had. Feed it Reloder 15 and any decent bullet and it shoots tight.

Example: the above mentioned load printed a six shot group on our 500 meter gong today that was only the size of an apple....a McIntosh. I leave it zeroed at 300 meters all the time due to a no knob Leupold 12x scope. I found a dirt clod in the berm about six feet above the gong for an aim point. First shot landed at 8 o'clock two inches in on the steel. So did the other five bullets.

Jim, I think that maybe I will bring the 788 down this April to the AZ State HP and beat your ass with it.

Even if one would be just as unpleasant as the other, I would rather have you beat my ass than examine it on any day!

Bob Mc Alice wrote:I worked my magic on the stock trigger long ago. Got it down to a 3lb crisp reliable break. No way would I put a $125.00 trigger in a $125.00 gun....no sir.

Your $125.00 rifle is now worth considerably more, maybe one of the better investments you've made.

Your right, Bob. They go for $400-$600 in decent shape on the various selling sites. I bought this one from a guy at work back in '80 who needed some quick cash. It was still in the box from when he bought it five years earlier. A couple of years ago I fooled a so called 788 expert at the range who had never seen a 24 inch barreled 7-08. You remember when I posted pictures when I modified a 700 barrel to fit the 788 ? The barrel marking ended up exactly where it would have been if factory installed. Remington only offered the 7-08 in a short 18.5" barrel in this model. I told him it was a custom shop version. He wanted to buy it on the spot, then I fessed up.

My brother bought a .44 magnum 18.5" in 1971 for about $100.00 and still has it. He never shoots it. It is worth $650. from what I have seen for sale.

Bob, as I've said before, I deeply envy your machine shop skills! Thanks for your posts!

Bob Mc Alice wrote:Remington only offered the 7-08 in a short 18.5" barrel in this model. I told him it was a custom shop version. He wanted to buy it on the spot, then I fessed up.

You broke the poor guy's heart. He thought he had a collectable factory "mistake" putting a long barrel on it.

Happy New Year!

Rick

Bob Mc Alice wrote:Your right, Bob. They go for $400-$600 in decent shape on the various selling sites. I bought this one from a guy at work back in '80 who needed some quick cash. It was still in the box from when he bought it five years earlier. A couple of years ago I fooled a so called 788 expert at the range who had never seen a 24 inch barreled 7-08. You remember when I posted pictures when I modified a 700 barrel to fit the 788 ? The barrel marking ended up exactly where it would have been if factory installed. Remington only offered the 7-08 in a short 18.5" barrel in this model. I told him it was a custom shop version. He wanted to buy it on the spot, then I fessed up.

My brother bought a .44 magnum 18.5" in 1971 for about $100.00 and still has it. He never shoots it. It is worth $650. from what I have seen for sale.

Bob, I have five 788's two of them chambered in 7-08 one with a custom Hart barrel and the other one with the factory 18.5" barrel that I used to shoot at CA and AZ state matches and also a few Nationals. I remember it was quite accurate and never did much to it since Hunter class was not what it is today and getting more than 50% of the targets with a 308 or 7-08 was an accomplishment at least for me. One year at Raton it rained hard during one match and the stock picked up a lot of moisture and I had a hell of a time trying to free float the barrel again so that it would shoot well enough again. My powder charge was 35 gr of IMR 3031 with 150 gr bullets for the first three distances and 168-175 for the rams. I picked that load because of the short barrel in the rifle. I never noticed the primers backing out like yours or the brass not lasting more than a few reloadings but really I only used the rifle to fire five or six matches a year. The other three rifles I have are chambered in .308, .222 Rem and .243 with no bolt and kind of rough looking, have tried to find a bolt but every time I saw one in the Internet they wanted way too much money for it. Two of my rifles have Canjar replacement triggers that are really nice (one of them was worked over by Roy Dunlap who was a very talented gunsmith and shooter back in the 70's). As you can probably tell my 788's do not get much use at all these days.