Check me on my swede bore diameter, planned mold size

[Andy]

Slugged my m96 barrel yesterday for the first time and got .263 across two opposing high points (are these called the grooves in this situation?) and .264 across the other.

I thought these rifles usually ended up .266-.268, hence the .268-.270 mold size that is usually desired.

Is mine unusually tight or is there a reason people want more than 2 thousandths over for these rifles? The rifle does look essentially unused. I was about to buy a mold off NOE but realized the only .266 molds are the 125 grain ones for the grendel, anyone know if they shoot well in a swede, or have other recommendations for a .266 mold if that is what I should get?

Thanks,
Andy

[Yodogsandman]

You really need to do a pound slug of your chamber, not just the bore. Do a few, sometimes you'll get a bad reading on just one. Those mold sizes reflect the body size that should fit your throat or free bore, located from after the end of the case mouth to the leade or beginning of the lands. This is the area that steers your boolit.

If the boolit is a bore rider type, the nose should be a tight fit on top of the lands to guide the boolit. If the nose is too tight, you'll have to seat it deeper into the case, maybe below the case shoulder. Look for engraving on the nose for best accuracy. Most prefer not to fit it so tight or have it engraved so heavily, that when removing a round from the chamber, the boolit gets stuck in the bore and is pulled out of the case. That just spills powder all through your action and is a pain to clean up.

This shows what and why...

http://www.bellmtcs.com/FAQ/ChamberThroats101.htm

http://castboolits.gunloads.com/showthread.php?168496-Chamber-and-throat-relationship

This is how to do it...

http://castboolits.gunloads.com/showthread.php?218414-FYI-This-is-how-I-do-a-pound-cast

[Andy]

So is it desired to have an oversize bullet that is pushed down to bore diameter by the throat? I would have thought .004" over bore diameter is too large a bullet regardless of the throat, is that not true? Very new to casting/reloading, so still learning the basics here.

[Yodogsandman]

Yes, a boolit acts kind of like bubble gum when smacked by pressure when fired. The tighter you can match the boolit to your chamber, the better to keep it aligned straight down your bore and prevent it from getting cocked or damaged during the initial launch. The only precaution is to be sure that the case neck can still expand a little (maybe .001-.002") to release the boolit during firing or excessive pressures will result. Check a sized boolit in a fired case neck from that gun for reference.

[Dutchman]

Lyman 266673 drops at 154 grains and .266" diameter. In my best shooting m/38 Gustaf it'll put 5 into one hole at 50 yds with some kinda powder charge I've now forgotten! Unique or 2400...

Dutch

[gnoahhh]

Yep. Size for throat diameter. .0005" under throat diameter is about right. Ignore groove diameter. Make the bore riding section of the bullet just kiss the tops of the lands and you're good to go. These protocols apply to milsurps as well as any other rifle.

[Larry Gibson]

I concur the bullet should be sized to fit the rifle's throat. However with milsurp Swedes I think you'll find the throats, while long, taper. Having measured several milsurp 6.5 Swede throats most of them in new or excellent condition taper from .268 to .266 near the leade. If you use a modern bore rider design cast bullet then .268 is generally the best sizing. However if you use a Loverin style cast bullet with driving bands you want to bump into the leade you will probably need a .266 sizer. Some lighter weight Loverin designs (129 gr or so) can be sized .268 and be slightly sized by the throat on chambering depending on alloy and if a slight crimp is used or not.

If you do a search there are a couple threads on the 6.5 Swede at high velocity:
http://castboolits.gunloads.com/showthread.php?72897-Testing-6-5-Swede-HV-loading-with-shotgun-filler

http://castboolits.gunloads.com/showthread.php?119495-6-5-Swede-HV-Finale

In those you will see the gyrations I went through to get my cast bullets to "fit" the Swede throats. Is what I did necessary? Not really, I now just size my 6.5 Kurtz and 266455s at .266 and they shoot just fine.

Larry Gibson

[Yodogsandman]

Lyman 266673 drops at 154 grains and .266" diameter. In my best shooting m/38 Gustaf it'll put 5 into one hole at 50 yds with some kinda powder charge I've now forgotten! Unique or 2400...

Dutch

http://castboolits.gunloads.com/archive/index.php/t-90033.html

[shaggy357]

Most of the Swedes have a brass disk on the stock. The disk will tell if the gun has been rebarreld and the bore diameter. Two out of my three like the 265 cast bullets just fine. The third only gets jacketed as I was dumb and sporterized it for hunting. Shoots sweet tho...

Steve :)

[Andy]

Thanks for the thoughts everyone. I was just able to trade for an ideal 266469 (loverin style) that the previous owner said drops .266 so this should give me a good place to start testing.