Bore rider throat fit?

[Clinton]

Still trying to get one of my two bore riding bullets to shoot in my bolt action 308 win. I originally tried the Lee C309-170 sized to .309 because that's the diameter they drop from the mold. I believe .309 was too small for my barrels throat because they slid right into the chamber and left heavy rifling marks on the first band. So I moved on to the Lee C312-185 and sized them to .311. Nose diameter of both bullets is the same at .300-.301 and the rifle leaves very light rifling marks on the nose but I had to lightly tap the 185 into the chamber with a hammer to get the driving bands into the throat.

So I loaded them anyway (because more is better right?) and put a light crimp on the bullet. I tested them at home to make sure the seating depth would not change by chambering and un-chambering them. Then I went to the range and before firing the 5th round I ejected it just to see and sure enough it came apart and left the bullet in the bore and nobody around (including me) had a cleaning rod.

So where do I go now? Order a .310 sizer and try to ease the fit in the throat or go with a heavy crimp?

[rsrocket1]

Next time bring a range rod with you :) Just a 3 piece cleaning kit is enough because you know you aren't "driving" that bullet out of the barrel, just a light nudge will push that bullet back out. A lot of those crazy bench rest shooters do the same. They have the bullet barely seated in the case in such a way that if a ceasefire is called, they wind up unseating the bullet and having to push it back out of the rifling.

So how did they shoot anyway?

Luckily my Lee 309 bullets (113, 170 and 200) all fit perfectly into the throat with zero clearance when sized to .309" and seated to a 0.3" depth. That leaves the top lube groove exposed and the bottom of the bullet right at the base of the neck.

[Clinton]

Only fired 4 rounds but not very promising so far.

[popper]

slid right into the chamber and left heavy rifling marks on the first band Sounds good to me, slight engraving. Crimp does NOT provide neck tension, proper expander does! Beagle the 170 & get a 310 sizer (generic size for 308). Go to HW store & get a sturdy brass rod to put in the rifle case.

[runfiverun]

I would read good steel's sticky on how to make a pound slug before I went any further.
then I would make one and measure that, next I would draw it on a piece of paper.
then I would measure your boolit and draw it on a piece of paper too.
now compare the two papers.
I would then read badger EDD's sticky on proper throat fit and study the pictures in that thread
before putting the pieces together.

[mdi]

Enco has 1/4"x6' brass rods for $8.95 + shipping...

http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=505-3714&PMPXNO=941962

[Char-Gar]

Your problem is the throat on your rifle. It is either too short or to small, or both for your bullet design and/or size. A cast bullet larger than the throat size will shave lead when entering and accuracy will go out the window. Let me suggest several ways around it;

1. Get a throating reamer and put a throat of sufficient depth and size in the end of the barrel to accommodate the driving band sticking out of the case mouth. Always remember the folks who design and make over the counter rifles, don't do so with cast bullet shooters in mind.

2. Use a bullet that does not have a driving band sticking out of the case mouth. I would recommend RCBS 170 SIL. This bullet can be seated down until it will chamber in your rifle and still have all of the body contained in the case neck.

3. In a commercial rifle barrel that does not have a worn throat, .310 would probably be a better choice of sizing diameter. That in itself might cure your problem.

There are several others that might work as well from NOE. I am thinking that 311407 Mod or the 165 grain Ranch Dog just might do the trick, but without your rifle in hand I will make no predictions.

So, the bottom line is either modify your rifle to fit your Lee bullet or get a bullet that fits your rifle. But at any rate, it is time to wean yourself off of Lee molds. There are much better, albeit costlier, products out there. However if properly cared for the high quality molds will outlast several Lee molds.

As an aside, I have four rifles (2 Winchester, 1 Savage and 1 Remington) in 308 Winchester and they all do very well with cast bullets. I don't use Lee molds.

[Clinton]

Well I started myself off with Lee molds mainly because I'm still learning and don't want to invest a lot of money in a mold that may not be designed for what I'm wanting to do. I figure once I have a better understanding of what I'm doing I'll take the plunge and buy some better molds. In the mean time please take a look at the latest thread I posted http://castboolits.gunloads.com/showthread.php?261206-Velocity-degrading-accuracy

Is it possible for the bullet fit not to be correct and still get those results at low velocity? At this point I'm still unsure if I've got the sizing/seating depth right or if something else is causing me grief.

[Char-Gar]

Well I started myself off with Lee molds mainly because I'm still learning and don't want to invest a lot of money in a mold that may not be designed for what I'm wanting to do. I figure once I have a better understanding of what I'm doing I'll take the plunge and buy some better molds. In the mean time please take a look at the latest thread I posted http://castboolits.gunloads.com/showthread.php?261206-Velocity-degrading-accuracy

Is it possible for the bullet fit not to be correct and still get those results at low velocity? At this point I'm still unsure if I've got the sizing/seating depth right or if something else is causing me grief.

I understood your post in this thread having to do with a very hard fit of the bullet into the throat, to the point that you had to tap it in with a hammer and the bullet pulled and remained in the throat/rifling when you tried to eject a loaded round.

I was not addressing your accuracy. This seems to be mixing apples and oranges. Accuracy concerns follow the proper fit of the bullet to the rifle. So what exactly is your concern? Did you have to drive the rounds into the chamber on the targets shown in the other thread? I am a logical and linear thinker and can't follow these threads that bounce around from one concern to another.

[Clinton]

No they chambered fine. I thought maybe the fit was too tight for good accuracy but now I don't think so.

[Char-Gar]

No they chambered fine. I thought maybe the fit was too tight for good accuracy but now I don't think so.

If they chambered with ease, the difference in accuracy will be found in the effect of velocity/pressure on the bullet. You didn't give the charge weights so it is impossible to even guess at the velocity/pressure of your loads. You did not give the alloy either, so all we are left with is guess work and general principals, which may or may not apply to your situation.

As the velocity/pressure increases, the need for a tougher alloy also increases. There is also the effect of bullet spin on the bullet as the faster it goes, the faster it spins. Also some bullet lubes roll snake eyes as the velocity/pressure increases.

4227 and 5744 are both good cast bullet powders, but when the pressure reach the level to push the bullets over 1,800 fps or so, it is time to go to a slower powder. Faster powders past a certain pressure point can deliver a blow to the bullet that will cause it to deform.

Without out more specific detailed information, that is about as good as I can do.

[Clinton]

Lets see, I tried 21 and 22 gr of IMR4227 and 19.5 and 20.5 of 5744. I still wonder if maybe I quit too soon but with accuracy that bad it would have to improve a lot and quickly. All bullets were air cooled COWW sized .311 and lubed with Lyman Orange Magic. OAL was 2.750. I've loaded them with IMR4895 for tomorrow and will see how that goes.

[Char-Gar]

Lets see, I tried 21 and 22 gr of IMR4227 and 19.5 and 20.5 of 5744. I still wonder if maybe I quit too soon but with accuracy that bad it would have to improve a lot and quickly. All bullets were air cooled COWW sized .311 and lubed with Lyman Orange Magic. OAL was 2.750. I've loaded them with IMR4895 for tomorrow and will see how that goes.

I have never used 5744 but have shot lots of 4227. I don't think more will help your problem, but only make it worse. 18 grains of 4227 should show an increase in accuracy for you, 16 to 17 grains might yield more accuracy yet.

In the 308 Winchester I used either 16/2400 or 50/WC872 and get all the accuracy the rifle has to give with either charge. In spite of the difference in charge weight, there is only about 400 fps difference in the velocity.

[Clinton]

Ok I'll give a lighter charge a try next time. Thanks.