7mm Compromise, T65/7mm

Ray, great info! Thank you very much.

Further to my comment about the FA 52 headstamped 7x51mm that I have with a Belgian S12 bullet, a picture is attached. At least, I have assumed it is a S12 bullet as it is CNCS and appears to have no cannelure.

The bullet is set slightly further out to give a greater OAL than the British rounds. The average of five British examples is an OAL of 2.79” but the FA is 2.828”. The case length of the FA is 51.05mm.

I wonder if we (the Brits that is) supplied FA with some S12 bullets as well as the Type B etc.?

In the picture it is alongside a British example, which is interesting in itself as the headstamp is “RG 52 7mm” and has been made from an earlier 7mm H.V. bunter with the H.V. removed. You can see that the 7mm is asymmetric to the rest. I think that must be one of the first 7mm Compromises made. Unfortunately it has been inerted.


Tony - You ask an interesting question. I have one of the same cartridges and I have seen several others. They seem to be just as common in England as well. I’ve heard two stories - 1) the bullets were supplied to FA and they loaded the cartridges, and 2) FA supplied cases to England and the cartridges were loaded over there. I suppose it’s also possible that both answers are correct.

What is missing, in my opinion, is the Belgian role in all of this. To what extent did they participate in the trials and what other Belgian experimentals might there be? You may recall Jim’s recent questions about a different LR cartridge that looked to have a Belgian connection, but no one was able to identify it, or even offer a guess.

There must be documentation out there somewhere covering the Belgian experiments. Maybe they were more interested in developing a rifle and left the cartridges to others?


I think on balance it is more likely that these were bullets supplied to FA for loading. Britain and Belgium were both making the S12 bullet in quantity at that time (or “Continental” or “Belgian Mauser” bullet as it was also referred to) and if we were supplying Type B and others, why not the S12 as well? The other question is why would the U.K. want FA cases to load? It was unlikely that we would ever need to load American cases and there was by then plenty of experience with British , Canadian and Belgian cases. In addition, I have never seen any reference in British documents to us loading FA cases. That does not of course mean it did not happen.

With regards to Belgium, by 1952/3 they were busy developing their own entrants to the BBC trials and trying to sell the FAL in 7mm Medium (2nd Optimum) calibre. They did develop an interesting rigid composite AP round that they loaded into the 7mm series. Mine is loaded in a 280/30 but I know they also loaded it in 7mm Medium and probably in 7mm compromise.

What is much less researched is the early work they did to replicate US trials with the 300 Savage. Jim has a round suspected to be from this series but little is known. It would be good to find further information on these trials.

Picture of FN AP below with regular 7mm rounds.



Sorry for the delayed response…here is a picture of the Canadian 7 x 49 rounds I have. Both are loaded and both are headstamped F A 48 (no star). The round on the left has a brass primer and the one of the right has a nickeled primer. It also has remnants of a pink tip. These rounds are from different sources (but both Canadian, and from long time collectors who were in the military). While consisting of non-Canadian components, I was told by both sources that they were Canadian.

Here is another picture of the US 7 x 49 (with green tipped projectile) and a NPE. They are pictured along side a 7 x 51. The x49 is headstamped F A 51 while the x51 is headstamped F A 52.

I can also post pictures of the other Canadian 7 x 49 and 7 x 51’s I have if anyone is interested.


Thanks Paul. Your FAT1E1/280 cartridges fit the description I posted not too far back. I suppose we will never know if they are Canadian or simply from a Canadian collector. I tend toward the latter since it would have been unusual for DA to be experimenting with Brit bullets in US cases at such an early date. And, what rifle would have been used to test them?

Regardless, more cartridges for us to look for. And, yes, I for one would like to see photos of the others.


Hi Ray,

I spoke to the gentleman from whom I got the round on the left. He got this round at the Dominion Arsenal lab. One of the techs there kept a little box of oddball things, and this round was in this box. He advises that this round was absolutely loaded at DA.

Here are some pictures of the Canadian 7 x 49 (2nd Optimum) and 7 x51 (Compromise) rounds.

7 x 49’s

The NPE case on the right is headstamped DAC 51 (.30-06 bunter)

7 x 51’s

The loaded round on the left is also headstamped DAC 51



Here are the 2 Belgian AP rounds I have. The 280/30 is a factory dummy and is headstamped 7MM FN 52. The 7 x 49 is headstamped F N 56.


Thanks for all that additional information, and the photos. Good stuff for the 3 or 4 of us interested in the .280/T65 cartridges. ;)


With regard to your comment “I think there is a common misperception that the US dismissed the .280 as a possible NATO cartridge, out of hand, when the opposite is true. They did consider it enough to do actual testing of different cartridges over a 3 or 4 year period but, as we know, opted for the .30 caliber, for various military, and political, reasons. But, that’s my own opinion only so take it for what it is worth.”

While the US may have evaluated a number of different cartridges before the final adoption of the 7.62mm NATO cartridge, US Army Ordnance would not seriously consider any cartridge that was not similar in stopping and wounding power to the .30-06. This long-held view was made very clear when the US finally rejected the 280/30 cartridge outright stating that “The Army is firmly opposed to the adoption of any less effective smaller caliber cartridge for use in either its present or in the new weapons being developed. Any new rifle cartridge must have the wounding power, penetration characteristics, and ballistics at least equal to that in use today.”

The trials comparing both ammunition and rifles that ultimately lead to the adoption of the 7.62mm NATO cartridge and M14 and FAL rifles were carried out with great objectivity. The same can not be said of US Army Ordnance’s the interpretation of the results.

The details of the politics, different ideologies, nationalism, dogmatic thinking, and economic reality story that led to the adoption of the 7.62mm NATO cartridge is covered in an article that I have just submitted to the IAA.


Dave, what is the chronology of Ray’s “testing of different cartridges over a 3 or 4 year period” and the “The Army is firmly opposed to the adoption” statement that you posted? Did the statement come before, during, or after the testing?


I think it would be more correct to say that certain individuals within US Ordnance were firmly opposed to adoption of any new cartridge of less than .30 caliber. There were others who held different views and, in fact, recommended adoption of a smaller caliber. In the end, the buck had to stop somewhere and the pro .30 caliber side prevailed.

Don’t forget, the Brits unilaterally adopted the .280 cartridge and EM2 rifle, (eschewing a NATO cartridge),but that decision was ultimately overruled. So, to be fair, I guess you’d also have to say that certain individuals within the British government were firmly opposed to the smaller caliber.

Anyone with a military mind knows that this was nothing new, nor did it end with the 7.62mm NATO. The 276 Pedersen and 5.56x45 are two examples. And, never underestimate “politics, ideologies, nationalism, dogmatic thinking, and economics.” They drive virtually all military decisions. I, for one, think that’s the way it should be. Otherwise, the boffins would rule the world. (Did I use that term correctly, Vince?)

I’m looking forward to your article.


I don’t dispute your first paragraph, but I think with the personalities involved there was little chance of a smaller caliber being adopted. You are correct in stating that the UK officially adopted the EM2 rifle chambered for the British 7mm Mk 1Z cartridge. The decision to reverse this decision came about because of a change in Government in Britain in the fall of 1951. The reasons behind this were several-fold, but I don’t believe that bullet caliber was one of them. The new prime minister Churchill had, in the interests of NATO standardization, firmly opposed the adoption of the EM-2 by Britain alone from the outset. His decision to abandon EM-2 and 7mm cartridge reflected the realities of Britain’s place in post-WWII Europe and NATO; Churchill realized that Britain needed to cooperate with the US and prevent rifts occurring that could jeopardize the security of Western Europe in light of the ongoing Cold War. Furthermore, Churchill saw that the UK small arms industry was not capable of re-equipping the UK army in a timely fashion without significant outside help. With regard to there being British individuals opposed to the smaller caliber, this didn’t prevent the Small Arms Development Committee (composed of Britain, Belgium and Canada) from attempting to develop between 1952 and 1953 a 7mm cartridge acceptable to NATO.

In response to Jon’s posting
The “The Army is firmly opposed …” statement was made in January 1952 (versions of it appeared in late 1951). However, I believe it reflects the predominant US Army’s view of the period under discussion (1945 – 1954) that the new cartridge should use a .30 caliber bullet and have similar stopping and wounding power to that of the .30-06, which in effect meant delivering a fatal wound out to 2000 yards. Many of the criticisms of the British .280 cartridge can be traced to this mindset. Despite attempts by the BBC to address the US Army’s criticisms, they were all based on a 7mm, not a .30 cal bullet and were doomed to failure because of this.


PS By the way, us “boffins” have our own “politics, ideologies, nationalism, dogmatic thinking, and economics” to deal with so we just don’t have time to rule the world!

7.62mm NATO or .280 NATO??? I’ll collect - you decide. ;)


I have to agree with Dave about the reasons for the rejection of the .280. To use modern terminology, there was an institutional bias within the US ordnance community against anything that was not a .30-06 clone in a modern case. In fairness to the US trial officers, they did recommend that although none of the rifles were ready for service and needed further development, the .280 was worthy of further development to meet the US criteria on residual velocity and penetration.

The reasons for Churchill’s decision to overturn the adoption of the EM2 and Mark 1z cartridge was partly pragmatice, in so far as the UK industry was simply too small to re-equip the army with the new weapon in a realistic time frame, but also because he was essentially a friend of the United States and did not want this to cause a rift in the crucial post war period when the cold war was rapidly developing. In hindsight he was probably right. Despite its potential, the EM2 was actually not really ready for service and would have needed a lot of futher development.


For what its worth, I think we too often confuse positions held forth by the end-users (US Army Ground Forces/Field Forces) with those held by the technical services (US Army Ordnance Department/Corps).

I fear that the development of calibers other than 0,30" by the UK were based on shaky foundations from the start.

Earlier this week I found this document in a file of general exchanges about the UK adoption of the 30-06 round. What’s most interesting is that it was not proposed to adopt the 30-06 as it already existed but to adapt it to current British manufacturing practices.

Happy collecting, Peter

[quote=“enfield56”]I fear that the development of calibers other than 0,30" by the UK were based on shaky foundations from the start.
Thanks for that, very interesting. However, it doesn’t necessarily mean that the .280 stood no chance. The way it reads to me is that at the end of the war the UK needed a rimless cartridge and the most appropriate one around to ensure future supplies was the .30’06 (the only serious alternative would have been the 7.92x57 already in British service, but after 1945 it didn’t seem to have much of a future…).

Then it was decided to develop a new cartridge as NATO’s standard rifle/MG round, with the USA abandoning the .30’06. At which point the British switched tracks and did their very best to persuade the USA to adopt the .280. I don’t think there’s any doubt that had the British succeeded, that would have entered general service throughout NATO (and maybe the 5.56x45 would never have happened).

That particular decision only stood for a very short time. The original decision to adopt the .30-06 as the future infantry round was taken by the General Staff in November 1942, but was replaced less than a year later in August 1943 by the decision that it would be the 7.92x57 round. Based on this the development of the SLEM1 rifle took place and plans were in place to make sufficient quantities for extended troop trials.

The 7.92x33 Kurz changed all that and together with the experience of the European battlefield post D-Day resulted in the setting up of the SACP in 1945. Quite why the General Staff decided to pre-empt their decision and re-visit the .30-06 has to my mind never been satisfactorily explained. In any case, six months later when the final SACP report was received in March 1947 the principle of a .27 inch round was rapidly adopted, so I do not think it was compromised by any previous thoughts.


I think that the .270 cartridge looks better balanced than the .280. In fact, it would probably be about right for a general-purpose round today, although it would need a heavier bullet to achieve a decent long-range performance.

Cris Murray’s 7x46 UIAC (Universal Infantry Assault Cartridge) has the same basic case measurements (diameter and length) apart from the fractionally larger calibre.