BULLBERRY CARTRIDGE LOADING DATA
Since Fred designed his 30-30 based cartidges more than 25 year ago we have sold hundreds of these calibers in a variety of firearms. Despite Redding making the Bullberry-based dies, we are still the primary source for the loading data. Feel free to download, print, share, whatever you need to access the particulars. We now have the individual caliber notes broken down into .pdf format for easier reference.
All loading data is the result of testing by Valley Shooter Supply, using an Oehler 33 Personal Ballistics Laboratory. With the specified components, this data proved safe in testing. Since neither Bullberry Barrel Works nor Valley Shooter Supply has any control over the components or firearm that may be used, no responsibility is implied or assumed for results obtained through its use.
PDF Loading Data Files:
All loads listed are shown from absolute maximum to the minimum recommended.
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Loads above those shown may display erratic/excessive pressure.
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CAUTION: Do not increase these loads above maximum charges shown!
Testing Method and Details
The loading data was developed using an OEHLER 33 Personal Ballistics Laboratory using Bullberry barrels. All loads were weighed or measured using a combination of a RCBS 5-10 powder scale and a LYMAN Autoscale. Dies by Redding in an RCBS Rockchucker press. Case forming was performed in an RCBS Ammomaster and trimmed on a RCBS Trim-Pro power case trimmer.
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No loads exceeded 48,000 psi at any time.
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The maximum loads were determined by firing multiple strings under different conditions on different days.
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Minimums were established using the same basic
criteria but the total number of strings, and rounds per string were reduced.
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Minimums are not the usual reduced by 10% as most manuals recommend. Because of the low fill ratio (powder to available space) the pressures became extremely erratic when reduced below the points shown.
Powder Selection
Fourteen (14) powders were tried with various bullet weights and cases:
General Notes on Powder
Rotating cases lengthwise end-over-end several times helps to uniformly distribute the powder and contributes to more uniform pressures and velocities.
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Ball type powders are contraindicated due to the low case fill ratio. Powder position is critical to pressure but appears to be less so for velocity.
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Powders located predominantly in the primer end give higher pressure versus lower pressures if at the bullet end, however, in the limited testing that was done to test this phenomenon (approximately 500 rounds) the velocity did not vary significantly, unless the powder charge was reduced below about 80% of the case-fill ratio.
Bullet Seating Depth
Bullet seating depth was determined by seating the bullet .025" from contact with the lands. Bullets seated deeper or further out can - and will in some cases - radically affect pressure without significant increase/decrease of velocity.
Fire Forming
Brass was first full length re-sized in a standard 30-30 Winchester die. The 6mm cases were then necked down using a tapered-shoulder 25 caliber die to a point slightly below the position of the base of the neck on the finished case. Cases other then the 6mm's were reduced in one step and by sizing in a tapered-shoulder sizing die for the appropriate caliber to the correct neck base position. Improved cases were then sized in the appropriate full length sizing die. All cases were trimmed to the correct length, those not requiring trimming were simply trimmed for uniformity.
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The powders used for fire forming varied by whatever was on hand, but the lowest reduced load of any loads shown will fireform without excessive pressure.
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"Sticky opening is a sign of pressure" — NONSENSE! At the point that sticky opening of the action occurs, maximum pressures have already been exceeded! This phenomenon can occur at 50,000 to 60,000 psi. Some frames appear to have a greater ability to not display this sticking even with loads that typically register above 54,000 psi. While the sticky opening is a good indicator of over-pressure it is not adequate to reduce a load by a couple of tenths of a grain and think that all is well.
Life of brass varied from as few as 15 loadings to as many as 30 as long as pressures were kept below 48,000 psi. The first signs of brass failure were cracked necks and low neck tension on seated bullets, followed by stiff extraction. Stiff extraction (not to be confused with sticky opening) is seen as difficulty in the extractor moving the brass back and out of the chamber (extraction).
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One or the other or both of these conditions can occur together. Stiff extraction is due to the brass losing it resiliency. Brass can continue to be used but extraction gets stiffer.
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Neck tension (bullet pull weight) does not seem to significantly affect pressures or velocity, variations are noted but unless the neck tension is so low that the bullet can be seated by hand, it doesn't seem to make that much difference.
