My Reloading Journey Thread

[eisenhower]

Okay, went to the indoor range today to test my .44 Special and Magnum loads using .430 bullets.

Good news was the accuracy was there ... this was 44 Special at 15 yds.



Bad news was leading, pretty significant, in about the first 2-3 inches of the bore. This happened on both the Ruger pistol and the Marlin carbine.

Looks like I'm going to need to go up to .431 and see if that stops the leading. That would be .002" over the bore size for the pistol, so hopefully that will stop it. The Marlin may require even larger.

DeWayne

[bigbore5]

What alloy are you using or did you buy the bullet? May be too hard. Also what's the lube? Often bought bullets use crayon hard lube. You're better off with a soft one.

[sharps4590]

Jun 23, 2024 21:54:44 GMT -5 bigbore5 said:

What alloy are you using or did you buy the bullet? May be too hard. Also what's the lube? Often bought bullets use crayon hard lube. You're better off with a soft one.

I'll second that with emphasis!  When you recover bullets and the lube groove is still half full of that hard, blue lube, don't try to convince me the lube is doing its job.

[eisenhower]

These were Missouri Bullet Co., 240 grain RNFP, .430, Brinell 12. Don't know what the lube is but it's blue.

[Cholla]

I recently bought some MBC bullets, the lube isn't too hard.

[bigbore5]

What size are the throats in the cylinder? If they're smaller than bore size you will have to get them corrected.

With only the first few inches of barrel leading and the soft alloy they may be obturating enough to seal in the barrel. Are you getting a lube star on the muzzle?

[eisenhower]

Throats are .4305", Bore is .429" ... don't know what a lube star is but didn't see anything odd at the muzzle when cleaning.

[bigbore5]

A lube star is some of the lube left at the muzzle on the grooves. Search lube star on here for some pics. If there's no star, your lube is failing.

[bradshaw]

REVOLVER ACCURACY is an ORCHESTRA of DIMENSIONS.

There is a temptation to assign great importance to dimensions we have the tools to measure----for example, it’s relatively easy to measure chamber exit hole (throat) diameter, and to measure groove diameter. Also, to give importance to details which can be altered with relatively inexpensive tools----for example, the forcing cone and muzzle crown.

The problem is, the bullet doesn’t care whether we have the knowhow and tools to isolate, measure, and fix a detail. We may obsess on chamber exit hole diameter, but have we yet quantified its relation to accuracy? Can we relate throat diameter to accuracy, say @ 50 yards, without factoring chamber-to-bore alignment, the forcing cone, bore & groove uniformity, and groove diameter? Do we think that a bullet which has been made crooked between chamber and muzzle gives a hoot about the crown?

Most of us haven’t a tool to measure chamber-to-bore alignment, and I submit fewer have the means to measure the included angle of a forcing cone. I cannot visually tell a 5-degree form a 7-degree or 10-degree or 11-degree forcing cone. I can generally tell the difference between the two forcing cones Ruger cut on SRM Blackhawk .357 Maximums. Bill Ruger, Jr., advocated a deep 5-degree included angle, I advocated a shallow 11-degree included angle. Both were used in production, and my serial 00018 had barrels fitted with each. I can tell them apart because my 11-degree is very shallow, and Bill’s 5-degee is deep. Lee Martin, who is as precise with machines as it gets, says he can’t visually read angles.

The devil's in the details... and combinations of details:

Of low importance to accuracy
* barrel/cylinder gap.
* muzzle crown.

Of moderate importance
* chamber-to-bore alignment. Maximum tolerable runout very much relates to forcing cone and throat diameter. Small calibers less tolerant the large bores.

Of great importance to accuracy
* bore unifoimity.
* bullet diameter or firm groove diameter.
* concentric, smooth forcing cone. Preferably shallow.

The TARGET is the FINAL ARBITER of ACCURACY.
David Bradshaw

[bigbore5]

Mr Bradshaw is correct and I often forget that very few people have access to the precision measuring tools I use daily. While I can accurately measure all the dimensions, you probably can't. I do precision work for a living.

[nicholst55]

I would slug the bore on that Marlin again. SAAMI spec for .44 Mag rifles is a .432" groove diameter.

[eisenhower]

I believe SAAMI for .44 rifle groove diameter is .431". Regardless, I couldn't slug the bore any better than I already did - I have crisp, clean impressions of every groove and I measure at .430". Unless my caliper is off, that appears to be what I've got.

[rjtodd]

Jun 25, 2024 23:29:56 GMT -5 eisenhower said:

I believe SAAMI for .44 rifle groove diameter is .431". Regardless, I couldn't slug the bore any better than I already did - I have crisp, clean impressions of every groove and I measure at .430". Unless my caliper is off, that appears to be what I've got.

Eisenhower,

As humbly as I know how, once you want to be certain to .001” or less, set your calipers aside and pick up a micrometer. Make sure it is zeroed and of reasonable quality and condition. Calibration is even better, but harder to do. I have older higher end (Mitutoyo/Starrett) but I suspect the modern Chinese makes will suffice for careful at home use. Pick one domestic my choice, and take the question marks out of your measurements. You wouldn’t measure OAL with a tape measure, and likewise you shouldn’t measure bore and throat slugs with a caliper. More accuracy is necessary.

Best regards,

Randy

[magpouch]

Very classy, and also very true.

[bryanaustin]

The old reloading tools may or may not work out for certain sized diameter bullets. Let me know how it works out. Many of the older tools don't resize much, nor do some crimp enough for smokeless loads. PLay with it and enjoy the heck out of it. My dad always said this kind of stuff is supposed to be fun ;-)