boolit selection for k-31

[mike in co]

Mike,

I have heard reference to this before but do not understand the reasoning of not wanting the bullet base below the neck. Both of my K31's require bullets seated very deep in order to chamber properly but they are also very accurate.

I have the 311291 in both SC and DC and the 311284 in SC. These cast too large on the nose to work well in the K31 but shoot great in my 03A3.

Charlie

1st......cause i said so.......lol....personal choice does count.

2nd.....you would have to see the nice round mark they leave in my chrono screens/sensors......yep my sensor housings are broken and pock marked from flying gas checks......culpret was some of those custom heavy 8mm boolits. if i can preclude it from possible occurence...i'm gonna. dispite all the talk..i got the damage to prove it. it may have been a fluke...but i'm not going there if i can help it.

[mike in co]

will someone measure the nose dia of that 312 160 lee.....

[bravokilo]

Maybe they have figured out that the "exorcism" comment wasn't meant for me. Or perhaps they have taken a close look at how you treat other members of this board when they happen to disagree with you. I can add more if you like.

http://castboolits.gunloads.com/showthread.php?t=1550

http://castboolits.gunloads.com/showthread.php?t=3566

http://castboolits.gunloads.com/showthread.php?t=10712

http://castboolits.gunloads.com/showthread.php?t=10865

http://castboolits.gunloads.com/showthread.php?t=11575

http://castboolits.gunloads.com/showthread.php?t=12355

BK

[mike in co]

...i took an antibiotic and it still won't go away.....

[texas tenring]

will someone measure the nose dia of that 312 160 lee.....

I just received my Lee 312-155 and cast a few the other night. The nose on that boolit cast at .309 with AC WW the front band is .312 and the driving bands are .3125.

I'm going to try this boolit in my K-31, as Ricochet said there is no throat the rifleing starts imediatly in front of the neck and it is about .308. My boolit engraves lightly but does'nt hang up in the chamber so I think it may work well, I'll give a report when I have a chance to shoot.

[mike in co]

sundog provided some rcbs 165's. at 2.780 oal they just sit in the lands. this puts the gas check a mere 0.025 below the neck, so i'll have to try this boolit. i think a better boolit would be to shorten the body of this aprox 0.08 . this would lighten the boolit from the 179 but also allow the shooter to tune the lenght to thier chamber.........more to follow.....

would someone care to send me a few of the lee 160 312 ??

thanks
mike

[brimic]

I recently received a new Lee 185-312 mould which I was hoping to use for Mosin nagants or possibly one of my tighter enfields, but its a no-go as it casts the nose at .298-299" (the bullet isn't quite round). Its even too loose for my rem 700 .308, so I'll try it in a K-31.

I have a lee 200-209 mould that I would have to seat almost the entire boolit in the case to chamber it in a K-31. I might be one of the lucky ones to receive a Lee mould that casts the nose slightly oversized at around .302"

[Bob S]

I posted this on the original Swiss Rifle Forum IRT a similar question. Some of it is reruns to some readers here, so to those I apologize for the redundancy:

The K31 can be a bit of a challenge because of the throat, or lack of it. My first efforts centered around the Lyman/Ideal 311291U. The "U" means "undersize". Since a lot of shooters thought it was beneficial to shoot bullets unsized, or sized very little, Lyman would continue to use a worn (undersized) but resharpened cherry to cut moulds and mark them "U". Usually this meant that the driving bands were closer to .309 than the .312 or so of moulds with a "new" (unworn) cherry. Unfortunately, it meant that the nose portion of the bullet would also be under sized, sometimes as small as .296. That was disastrous for most US .30 caliber rifles, but it works out well for the typical Swiss. The target below was fired with my first K31, which had by this time fired a few thousand rounds of jacketed bullet loads, so it had/has a "throat" of sorts, and I had no issues getting the old Lyman bullet to "fit". The groove diameter on this one is .307." The dispersion is 1-7/8", and as you can see it is almost all vertical. Heavier charges of slower powders, leaving less air space, may help.



The most reliable bullet I have found for the K31 is the Lee C312-1552R, which was designed by Ed Harris for the 7.62 x 39. On the surface, it seemed like an unlikely choice, but just seating some in dummy cartridges to check fit showed that it could be chambered in any of my K31's without intruding into the powder space. This is typical performance:



Extreme spread is just a skosh over 1-1/2". I have since found that bullets sized to .310 in this rifle with 16 grains of 2400 shoots just a little better, and it continues to shoot like this, day in and day out. Believe it or not, the groove diameter of this rifle is .3092".

This a 100 yard "Garand Match" target fired with this rifle and load. There are 34 shots in this target, 4 sighters (marked), ten shots standing slow fire (10 minutes) ten shots prone rapid fire (70 seconds); and ten shots prone slow fire (ten minutes).



The 1911 series rifles are much more forgiving with cast bullets because they have a real throat and will accept a wider variety of bullets, including a bunch of those old Ideal/Lyman with undersized noses. They following target was fired with a Gew1911 using Parker Hale sights, with no load development at all, just a first "guess". I was not firing for "group" here, this was for a postal match, and I was still "hunting" for a zero. The target is the 100 yard International Small Bore Target, A33. The ten ring is the heavy one, and it is about 1" in diameter:



The extreme spread is 2-7/8", and mostly vertical. How much of that vertical was me tinkering with the elevation I would have to find the data book which is buried somewhere. This load may benefit from a dacron filler.

I love the following target, because it proves the old adage that "no amount of skill will ever replace dumb luck". Ten shots fired prone, 100 yards, Gew 96/11 with the 311291, 16 grains of 2400, with a dacron filler:



I have not been able to repeat that one, but the rifle and load will reliably group 10 shots from the prone position into 2" or under. BTW, all of my testing is from the prone position. I do not shoot from a rest position, I don't believe in it. When I was firing itty bitty groups from a bench rest 40 years ago, and when I would go to a match and have to stand on my hind legs, or get into the sling in sitting, kneeling or prone, I found that I forgot how to shoot. I threw away that sand bags and have never regretted it. Once I did that, I started Going Places in the competitive shooting world. YMMV.

Resp'y,
Bob S.

[mike in co]

bob thanks for the repost. i have read most of your posts. we have disagreed about stuff but that is the nature of man. would you take a look at the group buy k31 post and post your 2 cents worth....
thanks
mike

[texas tenring]

I said I would post a range report as soon as I could get to the range. Finally after a month of snow and wet roads today was a very nice day, sunshine and very little wind just a little mud to deal with.

As mentioned in a previous post I ordered a Lee C312-155-2R mold to try in my K31. I did this after reading the results Bob S was having with this boolit in his K31.

I loaded 25 rds. total, 15 with 16grs of 2400 and 5 with 17grs and another 5 with 18grs. I got on the paper and shot a couple of groups with the 16gr loads they where 1 1/2"-2" not to bad. Then I shot a five round group with the 17gr load and shot a 1" 5 shot group at 100yds from the bench, I shot the other 5 rounds with 18grs and the group opened up again. I forgot to write it down but I think the 17gr loads were averageing around 1670fps.

The load was: 17grs. 2400 powder with the 312-155 boolit sized to .309 Lee push thru die gas checked and LLA lubed, CCI 200 primer, Graf brass and FL sized.

I'll have to load more of these and get the sights adjusted as I was just shooting for groups today. I'll pobably shoot this rifle and load in my club's monthly military match this next weekend. I can't wait!