There are several well-known firearm reloading die manufacturers. Those that come to mind include: RCBS, Lyman, Lee Precision, Redding, Hornady and Forster. Unfortunately, due to slight differences in chamber and bore dimensions of rifles, some brands of .40-65 Winchester die sets may not be compatible with your rifle.
To better understand why there can be differences in die dimensions you must understand that the .40-65 Winchester is not a SAAMI standard cartridge. SAAMI (Sporting Arms and Ammunition Manufacturing Institute) is an association of the nation’s major manufacturers of sporting firearms, ammunition and components. SAAMI is also an accredited standards developer for ANSI (American National Standards Institute) and is actively involved in setting industry standards and coordination of technical data. Although it’s not mandatory that firearm manufacturers adhere to the SAAMI standards, it is in their best interest to do so, especially those that are a SAAMI association member. SAAMI considers the .40-65 Win. an obsolete cartridge. Therefore, firearm manufacturers have somewhat of a “free hand” in defining the chamber and throat dimensions, and die manufacturers have to match the chamber dimensions to sell dies.
I purchased a Browning .40-65 BPC rifle shortly after they were introduced in 1996. After making a CerroSafe chamber cast, which I do with most all rifles I plan to shoot, especially those for black powder cartridges, I checked with several suppliers prior to ordering a set of dies. At the time Lyman indicated their 3-die set was designed to match the Browning chamber which has a well- defined (constant diameter) 0.5” long neck. Since then I’ve happily loaded many thousands of rounds using the Lyman dies, later adding a Lyman neck-only resizing die as a means to improve accuracy and increase case life.
The Browning BPCR has a “generous” chamber with a 0.436” diameter neck, resulting in a fire-formed 0.435” outside diameter case neck. Therefore, the fire- formed case must be at least neck resized then expanded to the correct diameter to hold even a “finger-seated” 0.410” diameter bullet. To eliminate having to neck resize and then expand fire-formed cases, and using Starline brass with a case neck wall thickness of 0.011”, one could have a custom mould made for a 0.412” diameter bullet. But unless the 1st couple of driving bands are reduced in diameter, the bullet will not slide into the 0.410” to 0.411” diameter extended freebore, common to the Browning .40-65 throat, and contact the leade. I’m seriously considering this approach and will likely have a custom bullet mould made.
A few months ago a Browning owner emailed me regarding reloading for his .40-65 BPCR. Attempting to save a few dollars over the more expensive dies, he’d purchased a set of Lee Precision .40-65 dies. The dies were well made but would not work for the Browning. After full-length resizing the cases, the expander and seating dies would not accept 0.408” to 0.410” diameter bullets, the typical diameter range for bullets used in the Browning. The bullets would not even feed into the seating die. It turns out the dies were designed for 0.406” diameter bullets for “cowboy rifles”. Given credit to the company, Lee offered to enlarge the diameter of the expander die and ream out the seating die to handle up to 0.412” diameter bullets, but by then the gentleman had purchased a Lyman die set.
At the March 2017 Texas State BPCR match, I was fortunate to win a substantial gift certificate towards a Shiloh Sharps rifle. Several months later the new rifle arrived - a very nice 1874 #1 Sporter chambered for the .40-65 Winchester cartridge. Being eager to try out the rifle, a few Remington cases, already reformed from .45-70, were quickly full-length resized and neck expanded with the Lyman dies only to find out the cases would not fully chamber in the Sharps. To identify where the case was contacting the chamber, the brass was coated with blue machinist die (a felt-tip black marker will also work in a pinch). It turns out the Lyman resized case diameter in front of the web (just forward of the rim) was the problem area, being slightly larger than the Sharps chamber. One option is slightly shortening the Lyman full-length resizing die, tapering and polishing the inside lip, resulting in additional resizing of the brass. But I remembered I have a RCBS .40-65 die set that came with a rifle purchased for resale. Fortunately I’d procrastinated in selling the die set on GunBroker or eBay. The RCBS dies, which are designed for the Shiloh Sharps chamber and 0.408” groove diameter bore, worked perfectly.
Although I have Redding and Hornady dies for handguns and other rifles, I have no experience with .40-65 dies from Redding, Hornady or Forster. I do suggest contacting your favorite reloading die supplier and at least questioning if their .40-65 dies are compatible with 0.409” to 0.410” diameter bullets. Also, as mentioned above, I highly recommend the 1st thing you do with a rifle you have yet to reload for is make a chamber cast or impact impression of the chamber and throat. The chamber and throat dimensions will better prepared you to have an intelligent conversation with a technical representative of the die supplier. Besides helping select a die set, a cast or impression will provide all the dimensions required for reloading ammunition for your rifle. If you’re unfamiliar with making a chamber cast or impact impression go to the article titled Chamber Casts and Impact Impressions.