Talk:.276 Pedersen

Revision with Patent Image

I've downloaded the Pedersen patent for the en-Block clip and dressed it up for insertion here. I've also moved the technical jargon to the bottom of the article and removed the technical tag. Sure, it's technical. You don't go to this page unless you want that kind of stuff. Any comments? --Asams10 01:32, 2 August 2005 (UTC)

Yes, great job and great graphic! I didn't think WWII was exactly looming in 1932, so I made a few edits in the timeline portion. HangFire 02:57, 17 May 2006 (UTC)

.280/30

Asam, the .280/30 is not actually a necked down 7.62x51 NATO. The .280/30 was created independantly from the T65/7.62 NATO cartridge and the only similarity is in its base, as the .280/30 was designed to have the same rim diameter as the .30-06 (which is the same diameter as the .308). It is not a 7.62 case necked down to accept a 7mm round - that would be the 7mm Compromise. The 7mm Compromise was a last ditch attempt to convince the Americans to adopt a 7mm cartridge by the British/Canadian/Beligians and is also known as the t65/7mm. It closely resembles the 7mm-08 with a MV of about 2700-2800 FPS, whereas the .280/30 only has a MV of about 2500 FPS. It is a minor point though - great article, I learned a lot! JamesL85 08:55, 15 January 2007 (UTC)

Asam, I see where you're going and it's a good start. But again the .280/30 does not replicate the ballistics of the 7mm-08. If we are going to mention the 7mm-08, ot would probably be best to mention the 7mm project in general perhaps like so:

Interestingly, British studies on various 7mm cartridges during the 1940s (in particular the .280 British) culminated in the 7mm "Compromise" cartridge which was the 7.62x51 mm NATO case necked down to fire a 7 mm bullet essentially duplicating the modern 7 mm-08 sporting round.

However, the Pedersen and the .280/30 are very similar and perhaps the 7mm-08 reference may not be needed at all. (.280/30 fires a 140 grain bullet at around 2500fps, whereas the .276 Pedersen fires a 140/150 grain bullet at 2400 FPS, versus the 150 grain 7mm-08 fired at 2800 fps which is the same as the 7mm compromise cartridge.) Perhaps we can write it like this:

Interestingly, the British studies on various cartridges culminated in the .280 British cartridge, which shared many similarities to the .276 Pedersen, i.e. the 7mm caliber and similar velocities .

Tell me what you think - thanks! JamesL85 18:46, 15 January 2007 (UTC)

Made a slight change to the last sentence and removed the 7mm-08 reference as the .276 Pedersen and .280 make better comparisons to each other than the .280 and the 7mm-08 which are quite different ballistically. JamesL85 01:14, 19 January 2007 (UTC)

More References

Can anyone who access to the "numerous magazine articles" listed under references please flesh that out a bit? It'd be a big help. I'll try to find some basic cartridge and reloading info. Arthurrh 00:57, 1 August 2007 (UTC)

Try "Cartridges of the World" by Barnes. It's the only one I'm aware of with reloading information (maybe?)--Asams10 03:25, 1 August 2007 (UTC)

Yes, I got that. I'm still hoping that someone can point us to the correct articles more specifically than just "various articles" for better verification, further info, etc. Arthurrh 04:40, 1 August 2007 (UTC)

Waxed vs. Lubricated ammo

"Waxed" is the more proper term. That is the term used by Julian Hatcher as well as John Pedersen in his patent for 'waxed' cartridges. Read the patent here: U.S. patent 1,780,566 The term 'lubricate' is imprecise as there was more than one reason for the coating. It served four purposes: 1) lubricate the case and ease extraction 2) protect the brass, primer, and bullet from corrosion 3) seal the bullet to prevent moisture ruining the powder 4) seal the primer to prevent it becoming inert due to oils, water, sweat, etc. In its day, wax coating was derided as 'attracting dirt' however this was not true in practice. The real reason for not desiring waxed cartridges was an unreasonable prejudice born from ignorance. I'd cite Hatcher on this one, but it's in 'Book of the Garand' and I left that copy back in the states. I did bring Hatcher's notebook, though, and I'll have to gander at it and find out what he said.--Asams10 11:51, 5 September 2007 (UTC)

The wax or grease used on heeled bullet cartridges of the era (and earlier) was more prone to collecting dirt and debris, same for the lubrication on lead bullets of type lubricated inside the portion seated into the case.

The hard, "dry" paraffin wax type coating on .276 pedersen did not suffer from this. However, it did pose issues for re-use of the case as the hot wax (after firing and ejection) would pick up debris which would stick to the hot, melted wax and the full catridge case would need to be stripped prior to annealing and reloading. (the US Army was very keen on re-use of brass for training purposes)

Additionally, a fresh round chambered when the barrel was hot, then left to cool could potentially end up stuck in the chamber due to the wax melting and then solidifying. (this would be much more severe when a chamber was worn enough to have slight pitting and roughness to allow greater adhesion)

This latter issue is one specific to closed-bolt firing cycles, thus didn't occur in the wax-lubricated 20 mm cannon ammunition used in the Oerlikon series (or the wax-lubricated 20mm Hispano ammunition used in British service to improve reliability). The USN also waxed or greased their 20mm Hispano ammo, but this was done by armorers just prior to loading. (photos indicate the wax/grease was brushed on in thick layers while the ammo was already loaded into belts, albeit experienced armorers would likely focus on coating the shoulder area specifically, as the main purpose was to compensate for the excessive chamber depth of the American M1, M2, and M3 hispano cannons, which led to loose seating of the rounds and tendency for light primer strikes ... a design flaw which the US ordinance department refused to change) ~2026-17334-09 (talk) 06:41, 7 April 2026 (UTC)

The context being that the Oerlikon and Hispano cannons both used open-bolt firing cycles, so projectiles sticking in the chamber was not a problem. ~2026-17334-09 (talk) 06:42, 7 April 2026 (UTC)

WikiProject Military history/Assessment/Tag & Assess 2008

Article reassessed and graded as start class dashiellx (talk) 11:07, 24 April 2008 (UTC)

јел може то мало на Српском —Preceding unsigned comment added by 77.46.210.131 (talk) 09:56, 24 February 2009 (UTC)

"Unique en bloc clip?"

Rare, yeah, but "unique?" Don't think so. Anmccaff (talk) 21:58, 4 March 2016 (UTC)

Comparison to 6.5 mm cartridges rather than 7mm

The bullet diameter of the .276 Pedersen is typical of that of 7mm catridges (.284" or 7.22mm), so saying it is comparable to the projectile of the 6.5mm Carcano or 6.5mm Arisaka projectiles isn't correct. (7x57mm Mauser would've been the most common cartridge of the era to use that bullet diameter)

On the other hand, the case dimensions of the .276 Pedersen are relatively close to the 6.5mm Carcano and Arisaka, with very similar base diameter and case length, though the shoulder is more tapered on the Pedersen case and lacks the semi-rim of the Arisaka. ~2026-17334-09 (talk) 06:51, 7 April 2026 (UTC)