CB in 300 WSM?

[CHD]

I am casting with Lino out of a Lee C309-180R and getting boolits at around 170 gr sized with GC's on. I have searched high and low for advice on reloading lower velocities for Cast Bullets and found http://www.gmdr.com/lever/lowveldata.htm to be helpful. Not many sources out there for reloading in the 300 WSM, so I'm looking to pick your brains. I went with Unique powder simply because it is one I have on hand for the loads referenced at the above site. Here is my rub, they keep loads really light. I just loaded up 10 rounds with 7 gr. of Unique, which is a bit over 1/10th the case capacity (hope to test them Saturday, weather permiting). I have never used fillers, and honestly don't know what to use nor where I can get it. The GMDR website shows the 7 gr. load is producing 10 shot groups of .85" at 1041 fps (distance isn't referenced, if thats at 100 yds Great!, but I'm skeptical). Anyone else out there walked this road before? Love some friendly advice here. I want to crank up the velocity without leading the barrel, but don't want 10 inch groups.


Thanks all
CHD

[Ben]

That is some " neat " software you're using. Very nice.
The 300 WSM is a big case for that small amount of powder to burn in. Guess that is why the bench rest clan is moving to small short compact cartridges.......just the opposite of what you're dealing with. Good luck with your project.

Ben

[NHlever]

You will find that the .300 has a stiff case, and that 7 grains of Unique will not seal them in the chamber. I would start with 12 grains of Unique. While I don't load cast in any Magnum cases ( don't have the rifles) that is my go to start load for the .308 Win, and usually in the 30-06 though that case will seal with 10 grains usually. There was some load information in the latest Handloader magazine about that caliber that is probably still online. The author was discussing seating cast bullets with the gas checks below the neck, but there was some load data for that cartridge too.

[CHD]

After loading up my test batch of ten last night I found the Lee C309-180R boolits contact the lands in my Kimber. I have gone from 2.8 OAL to 2.4 OAL just to get my bolt to close. I did slug my bore prior to buying my mould and got it at .3083; then sized to .309. I will have to go back to the drawing board on the bullet, thinking something much more pointy.

[Ben]

I know that .309 seems a logical choice, but many of my rifles that have a .308 bore seem to shoot at their best with a .310 " bullet. Your mileage may vary

[Blammer]

check your sizing and GC'ing operation, are you perhaps "fattening" the nose causing you to have to seat it deeper.

I also agree that the cases are pretty thick, I'd probably try a different powder too.

IMR3031 comes to mind.

[CHD]

I Mic'd it just now at .3092. Here it a picture of the boolit.
The nose is nowhere near as wide as the driving bands. What am I missing?

[rockrat]

I would ask what speeds are you looking for. For slower speeds, I think I might try Trail Boss. In my 338 WM, 4759 works VERY well. I size @.340" for it and my 338 ME.

My 338 WM @2,200 fps

[Blammer]

Is the nose (the flat shank part) the same dia at the bottom as the top?

easy check is to chamber a dummy round and then extract it. (or a live round just be careful)

then look at the nose of the boolit. Is it marked with rifling?

[CHD]

So here are some more pics of the predicament...
From Left to Right: 1,2,3
1. Sized .3093 and loaded in 300WSM, I attempted to chamber this round in my Kimber Montana. It is difficult to see in the photo but the Lands are connecting the front of the bullet.

2.Sized boolit pre reloading .3093 at driving bands, .3041 half way up bullet in front of the driving bands

3.Lead slug, passed through the full length of barrel. Measures .3081 on driving bands and .3027 half way up the bullets driving bands.

I am measuring the Groove (fattest part of bullet). It seems I need a narrower boolit forward of the driving bands that doesn't contact the lands. I can not size down anymore without getting blow by.
What bullet designs have you found that will work here?

[Maven]

Cory, As the post-sizing CB has a slightly flattened nose, are you inadvertantly expanding it (i.e., the nose) by sizing it? (The top punch may also do this I realize.) Also, can you seat the CB more deeply in the case, i.e., up to the crimp groove, and chamber it easily?

[sqlbullet]

I was at the range yesterday for lunch with my Remington 700 in 300 Win Mag. I tested two loads for accuracy.

The first was a great load, but not really reduced. Lee 309-200 gas checked and lubed with Felix lube, over 57 grains of H4831 + 1/2 sheet of TP. First group was 2.1" + the cold barrel flier opened it to about 3.5". Second group was 1.5" for 5 shots.

Second load I tested was the same Lee 309-200, but paper patched with no gas check. The patch covered all the lube grooves, but none of the nose (I actually seat, crimp then cut off any patch that is showing). Charge was 15 grains of Unique. Two groups, both about 3-4". The second group had one flier that was off the paper, so I don't know how far out it was.

I want to try this load again with gas checked bullets. The paper patch was an experiment, and they don't work well with the tight throat my Remington has. I also want to try some bullets without the gas check with this load.

I would suggest you will find a sweet spot somewhere between 12 and 15 grains of Unique with your bullets. I would also suggest that H4831, or another similar slow powder, will produce better accuracy, but more expensive loads.

Edit: I seat gas checked bullets to the crimp groove, and the paper patch ones out over the leading groove. I don't worry about the base extending below the neck.

[CHD]

Maven, I am sizing in a star sizer (no top punch). I see what your saying about the nose being somewhat flattened, but that is how all of the boolits have been dropping from the mold. The slug used to check bore size was the first out of the mold, I can't explain why the tip is more pointed (maybe bc. its pure lead?)
The only explanation I can come up with for the boolit not chambering is shown on both the slug and the boolit that has been chambered (unsuccesfully), they both show lands marks in front of the driving bands all the way up to where the bullet narrows to the nose. My bullet design isn't narrow enough in front of the driving bands to keep from snagging on the lands.

I have tried seating the boolit deeper and deeper; even to the point where 3/8" of the boolit is hanging out I am still unsuccesfull in chambering without a great deal of force being required to cycle the action. The lands are contacting the boolit very close to the nose. This simply wont work. The base of the boolit and GC is hanging down way too far into the case.

SQL- I appreciate you sharing your experiences reloading. If I can get my fit issues ironed out I will for sure be following your trail. What rifle are you loading for? Im curious if Kimber just makes an aggressive (deeper than normal) rifling. I cant see any way short of a pointy boolit working in this rifle.

[sqlbullet]

The rifle is a Remington 700 PSS. It slugs out at .308.

The bore ride nose of the Lee 309-200 fits fine, but two wraps of paper sized .309 and allowed to sit for a few days don't. Those noses read .311 in my calipers.

[NHlever]

It just sounds to me like the "bore riding" section ( nose area) of your boolit is casting large. Your mold could be oversized in that area, and that is just not allowing the boolit nose to ride on the bore , but is getting engraved by the lands instead. Alloy can change that, but I don't know if an alloy change would get you enough smaller to work. I have a Saeco .30 caliber 180 grain FN mold that is the same way. Most of the alloys I have tried produce boolits that are too large in that area to chamber. It doesn't take much to make the rounds nearly impossible to chamber. With the short neck those magnum cartridges have, I would be looking at the RCBS 165 grain bullet, or a similar design from other makers. I wasn't able to find the RCBS mold in stock, so I have the Lyman 160 gr. version on order now. Hopefully that will cast a size that will work with a couple of my guns. I like the bore riding cast bullet designs, but they are as likely to cast too small, or too large as they are to cast "just right".

[Roundball]

I learned my lesson on this problem. Having had some 458125 that would not chamber. It was possible to make a simple check. The lesson was to drop the bore riding portion of the bullet into the muzzle. If it goes fine otherwise there is a problem. Some folks have to learn not to to beagle a bore riding bullet-did not read that in a book. This keeps me from trying to figure these things out from the other end of the barrel. My thirty caliber molds have .300 diameter or there abouts bore riding portions.