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Discussion Starter #1
I have a couple of the t-99 .300 savage conversions,and I just wondered tonight ,how did they make those, i know the barrel is still a 7.7 barrel they just use the undersized .308 bullet, but the chamber is what Im wondering about..the .300 sav case is a inch shorter than the 7.7x58 so what did they do pull the barrels and cut off a inch and then re cut the chambers??? other wise one would think the cases would deform into little brass .410 shell looking things when fired. thanks,Dave
 

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Dave, I do not know what the “Standard” method was, but to shorten the barrel from the rear as you describe is a pretty standard gunsmith method for this type of job, for instance all of the early US M-1903 Springfields made from 1903 till 1905 or ’06 were converted to the shorter M-1906 cartridge this way (that is why they have an odd barrel length of 23 and some odd fraction of an inch rather than the planned 24” barrel length), also this is a way to convert .308 Norma Mag rifles to the more available .300 Win Mag. If you compare the chamber area of your converted barrel to a unmodified one, look where the reinforce starts (that is the enlarged area over the chamber), I think it would only take about 4/10ths of an inch shortening to allow a .300 Savage reamer to clean up the original 7.7mm chamber. It could also be done by boring out the chamber and putting in an insert and then chambering the insert but that is not such a good method, the insert could pull out. Putting in an insert in the chamber would be the least desirable way, the neck of the 7.7mm is too long and I think the differences in body taper would prevent this from working (works for converting .30-’06s to .308 though, body taper is the same).
 

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Thanks ,Vis, It just got stuck in my head tonight before work when I was messing with my .300's ( Im playing with the idea of building custom ammo for one of them ) and the conversion method was bugging me all night.
 

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300 Savage

Back when they were doing this they advertize that they just removed on thread and set the should back. By setting back one turn they did not have to re-align the sights. Some day I will measure and see what one thread is in barrel length. riceone.
 

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Dave,
I had one once and also read about this. I'm like Roy, I thought it was take off one turn, but it could be two.

The rifle I had was missing the shoulder at the chamber, which would be at least 0.2"; the 7.7x 58 is approx. 1.88 to the shoulder the .300 Savage is 1.56 to the shoulder, which would indicate that at least 0.30 would have to come off the bbl.

This would be more like 4 threads and would have to have the shoulder and threads moved that much forward to screw in properly.

The picture below shows a .300 Savage on the left, with a 7.7x58 round.

Hope this helps. If you decide to make one, let me know- I'll send you the leftover box of .300 Savage I have.
 

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Discussion Starter #6
I have 2 of the rifles Don...Im just playing with trying to reload some with a .312 bullets vs the .308...Same lines as the 7.7 x 06 ammo Im playing with..im sort of fascinated (obcessed maybe) with the question of wether the conversion guns would perform better with the correct diametre rounds..as well as a spitzer bullet should perform better than the round nosed .300 savage ..My sportered one shoots acceptably for whitetail and such at 100yds but I just belive it could do better with a correct load for its radical chambering.how they made the .300 round fit was puzzling me tho.
 

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Discussion Starter #7
Oh Don, Do you still have the beat up 30-06 conversion you had for sale at the shoot out last spring?
 

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.30-06

I do, or did, till Doss and I took it apart this past weekend and decided it was a 'real' Korean conversion; so now it is a restoration project.

I have some spitzer .300 Savage. I'll send it to you. 19 rnds. like the one in the picture.

The .300 should do better with .311 bullets regarding accuracy.
 

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Cool ,I thought it might have been legit when i looked at it, glad to hear it turned out to be, I just was sort of wanting one in a less than pristine condition to test ammo thru,if you ever end up with a sportered one or something ,Please let me know.Dave
 

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I have a late Nag-6 in 300 Savage, the rifle is still in " full " military stock and hardware. The Bore on mine is a tight .300 - .311 and is not chrome. It does not seem to care much about bullet size, it shoots about the same with .308 or .312 bullets, but did not like .311 ??, or boattails . With it's best loads and the factory iron sights it is good for 2.5 to 3.3 5-shot group averages at 100 yards. It DOES pick up about 100 fps with a .312 bullet over the same load in .308 . Mine has a short chamber neck from the conversion, so I have to shorten my .300 cases to 1.823 to clear. Loads tried : I-3031 - 35.4 gr , Horn .308 150 sp at 2.507 ocl for 2282 fps , acc = 2.43 ,,,, same load .312 H-150 sp for 2374 fps, acc = 2.67 ,,,,, same load .311 SI-150 sp at 2.538 ocl for 2343 fps , acc = 3.86 ,,,,, Rem .3105 180 rn I-3031 - 34.2 at 2.360 ocl for 2333 fps , acc = 3.23 ,,,,, Boattails : .311 SI-174 mk - I-3031 - 34.2 at 2.360 ocl for 2217 fps , acc = 4.11 ,,,,, .308 SI-150 mk I-3031 - 35.4 at 2.559 ocl for 2214 fps , acc = 3.78 ,,,,,,,,, And last a "high speed " load : .3105 H-123sp I-3031 - 35.4 at 2.540 ocl for 2550 fps , acc= 4.35 . I kept the powder charge the same on most load to see the bullet performance difference. It MAY be the rifle just likes the Hornady 150 sp type bullet as it shot best with it .308 or .312 . It did lose velocity , and accuracy with the boattails. Watch for chamber " problems" as I am sure all the conversions are a little different. mag
 
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