Peterson Brass 300 Winchester Mag Unprimed Bulk Box of 250

Peterson Brass 300 Winchester Mag Unprimed Bulk Box of 250
Item #:PCC300WM250
$1.55 per piece
Shipping: One flat fee of $12.95 per online order.
Exclusions apply. Click for details.
Availability:In Stock
Due to the packaging and shipping process, case necks are often slightly dinged or bent and need to be rounded up and sized to give proper neck tension. New and/or fired cases must be full-length resized or have the expander ball of the sizing die run through the case neck prior to loading.
Read 7 Reviews

Product Information

300 Winchester Magnum

This is a Bulk package of Peterson Cartridge casings, they will not come in one of their plastic ammo boxes.

Made in the U.S.A.


Peterson makes the traditional SAAMI spec’d version that headspaces off the belt. But it also makes a version that headspaces off the shoulder. Peterson calls that version the .300 Win Mag- Long. This listing is the SAAMI spec version.

“I am extremely pleased to announce that as of July 20th, 2020, Peterson Cartridge has now added .300 Winchester Magnum brass to its’ product line,” stated president, Derek Peterson. “The road for us to produce this belted magnum case has been long, frustrating, and expensive. It has taken us over three years to release this cartridge and cost us well over $50,000 in experimental tooling alone.”

Peterson continued, “Producing a brass casing with a really good belt is a difficult thing. Getting the tooling just right is an iterative process, and these .300 Win Mags took more iterations than I care to remember.

“To make a new caliber casing for the first time, we design and order all the tooling. After it arrives, we do what we call a proof-of-concept (p-o-c) run. With most of the 30+ new tool packs we’ve designed, we end up with a “Best Vision” casing after one or two iterations.

“But these .300 Win Mags! With many of the p-o-c runs, the resultant belt wasn’t crisp enough. So we would redesign and order different tooling and try again. With some runs we’d get a good belt, but it wasn’t in the exact correct location. Some runs, the belt was good and in the correct location, but the equipment wouldn’t run it efficiently or the scrap rate was too high. It took a few different tooling iterations to get the grain structure in the casing walls just right. After some of the failed iterations we would speculate, maybe the problem is with the dimensions of the brass cups we are using as raw material. So, we’d redesign those, and try again.

“But after three years of unsettling self-doubt, and countless iterations WE GOT THE BELT. We can now make belted magnum casings! And we have really good .300 Win Mag casings on the shelf, with as good a belt as any in the industry. Our ballistician has shot some of these 20 times in a row, at SAAMI max pressure, with a minimum shoulder resize and they are still holding up well.”

Peterson concluded, “If you are one of the many customers who’ve called us every week to say, “When are you people ever going to release .300 Win Mag,” we have two responses. First, thank you for waiting. Second, FINALLY, here you go; we got the belt!”

Warning: Only use Peterson Cartridge Co. casings in firearms in good condition, designed, marked, and chambered for this cartridge. Do not use Peterson Cartridge Co casings for “fire forming” or any other purpose other than what they were designed and tested for. Peterson retains no responsibility for the enclosed casings if they are used outside of the manufacturer’s recommendations.

This is not loaded ammunition.

Read 7 Reviews - Average Rating: 4.7 stars

Peterson Brass

By Andrew H. on Mar 18, 2023
Great brass. Very consistent. It lasts much longer than other brands.

Not quite as high quality as expected

By Keith O. on Feb 14, 2023
Based on everyone else’s lavish praise I was expecting more. It’s good brass “overall”, but take the ball micrometer to the neck and you will get some pieces that are the expected .014 uniformly around, and others that swing from above .015 to below .013 as you make the loop (about 25% inconsistent). The normal flash hole uniform work is needed, some with very little to be done and others that need the work, but not unexpected. And lastly the overall length is a little short of Spec at 2.610, and seems to all be in the neck. For the already short necked 300, I would love to have that extra .010 on there.

300 Win Mag caces

By M A M. on Jan 24, 2023
Graf & Sons,
Shipping was quick! Pricing was good, and the brass are in great shape. Very consistent from one case to the other.

Premium Brass

By Michael W. on Mar 08, 2021
First time ordering Peterson brass. This is Some of the best brass I’ve ordered. Equal to Lapua in my book.

Peterson Brass: Top Tier Brass

By Charles B. on Nov 27, 2020
This brass is top tier. Uniform measurements and weight consistency right out of the bag with nearly no packaging and transport dings/dents. Is standing up well under 4 firings and 3 runs through the FL sizing die with no sign of stress as of yet. The Quality is definitely as good as the First-Names in Brass that we are all familiar with. Highly recommended!!!

Peaterson Brass

By Thom B. on Nov 06, 2020
Very consistent, low extreme spreads. Worth the price.

Peterson Brass

By JOHN N. on Nov 05, 2020
I have been waiting for over two years for this 300 Win Mag brass and I can't be happier. Out of 250 cases there were only "7" that were out of a range of 1 1/2 grains.The cases were true and no flaws in any of the cases. With very little touch up they will be ready to load.
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