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Larry Gibson
08-01-2006, 03:48 PM
Anyone know if the barrel shank diameter and threads are the same on the M788 as on the M700? I've got a M788 .308 that could use a new barrel and Midway has some pre-threaded Shilen match grade 26" varmint contour barrels in their flyer for a decent price. I can adjust the shoulder correctly and finnish chamber them.

Larry Gibson

Mk42gunner
08-01-2006, 04:40 PM
Larry,
I remember reading someplace, maybe in one of the Gunsmith Kinks from brownells that they are different. I think the 788 is larger in diameter with a longer shank, but can't prove it right now. My copy of bolt action rifles 3rd edition doesn't have the barrel shank dimensions for the 788 in it.

Good Luck

Robert

bravokilo
08-01-2006, 10:11 PM
According to "The Bolt Action Rifle" by Stuart Otteson (Vol 1, Winchester Press)

Rem 700

Thread 1 1/16" X 16

Engament .69 (11 threads)


Rem 788

Thread 1" X 20

Engament 1.1" (22 threads)

You COULD at least rethread the 700 barrel to fit the 788...


BK

Larry Gibson
08-02-2006, 06:36 PM
Thanks guys, that's exactly the quick and accurate info in respnses I've come to expect from the fine people here.

Larry Gibson

versifier
08-04-2006, 12:08 AM
Larry,
Whatcha gonna pick for a chambering?

Larry Gibson
08-04-2006, 12:36 PM
Larry,
Whatcha gonna pick for a chambering?

Probably going to stick with .308 since I have a gob of componants and moulds. After my last post here I was in contact with a gunsmith friend in Oregon that has a very little used Pacnor (SP?) Palma barrel. It is a 30 incher and has a long shank so there is plenty to set back 1" and rethread for the 788. Twist is 1-13" with a .209" bore and .307" groove depth. He said the guy worked up a load (sub MOA) shot one match and decided he needed a 6.5x284 instead. With that tight bore and slow twist plus I'd shorten the barrel to 26" it should be a cast bullet shooter extraordinair. It will cost about the same as the Shilen barrel. I'm giving serious thought to it.

Larry Gibson

Bass Ackward
08-04-2006, 12:58 PM
Probably going to stick with .308 since I have a gob of componants and moulds. After my last post here I was in contact with a gunsmith friend in Oregon that has a very little used Pacnor (SP?) Palma barrel. It is a 30 incher and has a long shank so there is plenty to set back 1" and rethread for the 788. Twist is 1-13" with a .209" bore and .307" groove depth. He said the guy worked up a load (sub MOA) shot one match and decided he needed a 6.5x284 instead. With that tight bore and slow twist plus I'd shorten the barrel to 26" it should be a cast bullet shooter extraordinair. It will cost about the same as the Shilen barrel. I'm giving serious thought to it.

Larry Gibson


Larry,

Just understand what you are getting. Most Palma barrels are made tight, but they are usually only 3 or four groove.

While the twist rate is accomodating, your rifling height is not if you only have 3 or 4 drive lands. If this is the case, then "I" would go the Shilen route just because I would want 8 lands of the same height pulling for me. Better odds with softer lead at high velocity. Of coarse, IMO.

Jumptrap
08-04-2006, 01:04 PM
Well, opinions are like *******s.....everybody has one. I wouldn't give a hoot how many lands and grooves it had......too many 2 groove Springfield barrels have prooved their mettle with cast bullets. In fact, my next barrel will be a 3 groove Lilja...if and when i have a nother gun built.

Me also thinks, if I were going to make a cast bullet rifle, I'd go with the 308x1.5 and get rid of that unneeded capacity of the standard 308.

Randy in Arizona
08-29-2006, 03:18 PM
Pacnor (SP?) Palma barrel with a .209" bore and .307" groove depth. Larry Gibson


Now that is some seriously deep rifling!:kidding:

Larry Gibson
08-29-2006, 07:57 PM
Well, opinions are like *******s.....everybody has one. I wouldn't give a hoot how many lands and grooves it had......too many 2 groove Springfield barrels have prooved their mettle with cast bullets. In fact, my next barrel will be a 3 groove Lilja...if and when i have a nother gun built.

Me also thinks, if I were going to make a cast bullet rifle, I'd go with the 308x1.5 and get rid of that unneeded capacity of the standard 308.

Well it just so happens that 20 years ago I had a brandy new 2 groove barrel. I had it set back and rethreaded and rechambered to my own CBC (Cast Bullet Cartridge) because I had bought the Idea that the 2 groove was just the ticket for cast bullets. I also wanted just enough case capacity with 4895 to drive a 220 gr bullet at 2100 fps. Included was the need for a '06 length neck. With the help of a Powley computre I found a .308 FL die could be shortened to give the correct case capacity. The shortened case when trimmed to 2.0" has a '06 length neck. The gunsmith was able to use a .308 reamer to initially chamber and then used an '06 reamer to lengthen the neck.

Sounds great right!(?) Wrong. I quickly found that withalmost 100% loading density and a 311284 cast hard that velosity was 2150 fps but accuracy was 2-3 MOA at best. When I reduced the load to a velocity of 1750-1800 fps accuracy was MOA. Same-same with 311291, 311299, 311041 etc. ad nauseum. Accuracy was just the same as other '06s with the same bullets at the same velocity. Only saving was a 1 gr decrease in 4895 required for the same velocity in the CBC. I also quickly discovered that the 2 groove barrels gave simualr accuracy at 100 and maybe 200 yards as 4 groove barrels. However at 300 yards the groups of the 4 groove barrels were consistantly better than those with 2 groove barrels. Ever wonder why no 2 groove barrels are used in match rifles? The answer is obvious.

I was not aware that the killer to accuracy with cast bullets is RPM. Two or four groove barrel did not matter out to 200 yards if I exceeded 135-140,000 RPM accuracy fell off. The only benifit my CBC gives vs the original '06 is I can shoot the same bullet at the same velocity with the same accuracy in the smaller capcity CBC without using Dacron fillers. I'm not really sure that is worth it though. I'll try to post a picture of the CBC tomorrow.

Larry Gibson

Larry Gibson
08-29-2006, 07:58 PM
Now that is some seriously deep rifling!:kidding:

Ooops! Should read .299".

Larry Gibson

Larry Gibson
08-29-2006, 08:10 PM
Larry,

Just understand what you are getting. Most Palma barrels are made tight, but they are usually only 3 or four groove.

While the twist rate is accomodating, your rifling height is not if you only have 3 or 4 drive lands. If this is the case, then "I" would go the Shilen route just because I would want 8 lands of the same height pulling for me. Better odds with softer lead at high velocity. Of coarse, IMO.

I'm debating that one also. I've a couple barrels with 8 grooves and 1-12" twists. I've not gotten excellent accuracy above 1650 fps with soft alloys (as would be used for hunting). I have tried several different bullets with the same results. Hard bullets will push 21-2200 fps with excellent accuracy in these barrels. I would get the 4 groove barrel. With the .004" deep grooves and the 1-13" twist a soft cast 311041 should go 21-2200 fps with excellent accuracy (1.5 MOA). Maybe 23-2400 fps with acceptable hunting accuracy (2-3 MOA). I can come close to that out of my 26" Scnieder barreled M70 Match .308 rifle with 1-12" twist. Guess the proof will be in the shooting so one of these days I'll have another go at it. Unfortunately I've codgitated too long and the barrel has been sold. Perhaps a 1-14" twist?

Larry Gibson

Larry Gibson
08-30-2006, 11:27 PM
Here's the .308 CBC with a 30-30 to the left, a .308 and '06 to the right. I use U.S. 7.62 brass to form the .308 CBC as it gives less case capacity and the necks are turned (also annealed) to give minimal expansion in the chamber neck. Again the case capacity was computed to drive the 311284 at 21-2200 fps with near 100% loading capacity using 4895. Also a picture of the M93 (1928 Oviedo) with the 2 groove barrel. Note the rifle is cocked; it has been converted to cock on opening with a lock time very simular to a M70.

Larry Gibson

Bob S
09-01-2006, 11:34 AM
Larry:

After the '92 Palma match, I put an Obermeyer 5R Palma barrel on my .308 788 to make a "poor man's Paramount". If you decide to go that route, I think you will be pleased.

(I had to shoot the '92 Palma with a Navy-issue Model 70 International ... it was the only thing in the inventory that met the Palma rules and might have been competitive. It was only AFTER my dismal performance that I discovered that the particular M70 that I drew had been Web Wright's for the CISM match in Cairo, and he had it set up for Sierra 190 grain MK's ... 10" twist and long throat.)

Resp'y,
Bob S.

MOSM
09-06-2006, 03:08 AM
The 788 thread is 1 inch diameter x 20 TPI, I think, whereas the Rem 700 is 1.0625 x 16 TPI.
The 700 barrel may possibly be used on a 788 but the shank on a 788 is quite long. I can't recall length off hand.
Naturally the reinforce of 700 barrel needs sufficient length to be fitted to a 788.
I suspect the standard Rem 700 has sufficient diameter to allow it to be fitted.
The measurements would need to be checked but at least you will know now that a 788 barrel can not be fitted to a Rem 700.

As an aside I consider the 788 a great bed on which to build a cast bullet rifle though the triggers are problematic.
I did see one fitted with an Anshutz match 22 trigger, here in New Zealand.

regards

Mosm

Willbird
09-06-2006, 06:28 AM
One thing to think on too, the 700 has the counterbore for the bolt nose, the 788 may not use one (my 788 is a 30-30, never looked at a rimless 788 bbl)

also typically the minor dia of a thread is (dia - thread pitch) that would leave the minor dia of the 700 bbl thread the same size as the 788 thread OD, you might end up with a ghost of the 700 thread left, however it would do no harm.



Bill

9.3X62AL
09-06-2006, 12:56 PM
Lotta good info for me here, since I am at a crossroads with one of my Rem 788's (in 22-250). I bought this rifle for low bucks, knowing that through long use its throat had been "Weatherbied" pretty deeply. So much so, I have to seat Sierra 60 HP's to OAL of 2.460" to be .020" back of throat leade! It shoots "all right", 5 rounds into 1" pretty regularly, with 1 sometimes creeping out .100" to .200" further. So, it is usable at a rat rifle.

Still, I'm not sure that a 22-250 gives you much more rat capability than you get with the 223, and the 10% velocity gain comes with using 40% more powder per shot, and throats burn out much faster. I have dismissed the idea of re-barrel to 22-250 for this reason, and pondered a re-barrel to 250 Savage--a caliber I much admire. Now, I'm leaning toward just selling the 788 as-is, adding it to a brace of shotguns I'm going to unload at the same time. Other toys beckon, and I have enough shotguns to outfit two shifts of cop cars at my old station assignment.

versifier
09-06-2006, 01:56 PM
Al,
I think the .250Sav would be a fantastic chambering for a 788, although the .358 has a lot of appeal, too. I think it is the best action Remington has ever come out with, despite its length limitations. For a cast boolit rifle, the length is no limitation at all. As soon as you sell it (and I really hope you don't) you will decide on the perfect chambering for it and wish you still had it. But, if you really have to let it go, unload it to someone here on the forum who will appreciate it. Personally, I'm still kicking myself for selling two of them over the years, including a .30-30 :( , but I did hang on to a .308 and a .22-250 and those I will not part with. Both are capable of .5MOA or less with their preferred loads, the .22-250 will do .33MOA on a good day, and I've almost got the .308 down to 1" @ 100yds with cast. I will be deer hunting with it this fall. I have been looking for one with a small (.223) boltface for years now to put together with Roy Dunlop's test barrel for the .30/.223. I never seem to have any cash when I find one, and they're always sold before I can get the money together. One of these years....