Calibre Definition Question

[castbullets.co.uk]

First of all, apologies if this has been asked and answered before - I did search to no avail but I might be looking with the wrong terms.

Anyway, my question: What specifically defines a calibre for the purposes of an ammunition slot on a UK FAC?

The nuance here is because I tend to use Lapua brass where I can, and in 7.62x54R Lapua only make 7.62x53R cases. From what I know of the specifications of the two cartridges, they are interchangeable unless you have a chamber cut for the absolute minimum dimensions for the 53R. A fired 53R case might well have a neck length which exceeds the 53R spec of 53.5mm and a trimmed 54R case might fall below the 53.7mm length of the 54R spec. Lapua themselves (at least per Wikipedia) "does not make a difference between the 53R and 54R, but produces cartridges that will function in weapons chambered for either one."

So if someone were to load a cartridge up for use in a rifle chambered in 7.62x54R with a certificate allowing the rifle and ammunition as 7.62x54R but the headstamp of the brass says 7.62x53R, are they breaking the law even though a 7.62x53R case falls inside the C.I.P spec for 7.62x74R?

What if that person were instead to take a 6.5CM case and neck it down to 6mm for their legally-held 6mm CM rifle/ammo combo - the headstamp would of course be wrong but the cartridge would be correct... Same if they took some .30TC brass and necked it down to 6.5CM and any number of other situations where the headstamp alone doesn't indicate that the holder is in possession of something they shouldn't have.

Of course the chances of this coming up are small but I'd like to cover my bases if at all possible...

 

[grandad of the woods]

Interesting question

 

[shakey jake]

You are confusing calibre and chambering.
I would argue the head stamp is irrelavant. The round will only function properly in the correct chamber

 

[maximus otter]

First of all, apologies if this has been asked and answered before - I did search to no avail but I might be looking with the wrong terms.

Anyway, my question: What specifically defines a calibre for the purposes of an ammunition slot on a UK FAC?

The nuance here is because I tend to use Lapua brass where I can, and in 7.62x54R Lapua only make 7.62x53R cases. From what I know of the specifications of the two cartridges, they are interchangeable unless you have a chamber cut for the absolute minimum dimensions for the 53R. A fired 53R case might well have a neck length which exceeds the 53R spec of 53.5mm and a trimmed 54R case might fall below the 53.7mm length of the 54R spec. Lapua themselves (at least per Wikipedia) "does not make a difference between the 53R and 54R, but produces cartridges that will function in weapons chambered for either one."

So if someone were to load a cartridge up for use in a rifle chambered in 7.62x54R with a certificate allowing the rifle and ammunition as 7.62x54R but the headstamp of the brass says 7.62x53R, are they breaking the law even though a 7.62x53R case falls inside the C.I.P spec for 7.62x74R?

What if that person were instead to take a 6.5CM case and neck it down to 6mm for their legally-held 6mm CM rifle/ammo combo - the headstamp would of course be wrong but the cartridge would be correct... Same if they took some .30TC brass and necked it down to 6.5CM and any number of other situations where the headstamp alone doesn't indicate that the holder is in possession of something they shouldn't have.

Of course the chances of this coming up are small but I'd like to cover my bases if at all possible...

l also would argue that the headstamp is irrelevant. You have a rifle of 7.62 x 54R and “ammunition suitable for use in it.”

maximus otter

 

[cjm1066]

Calibre is the size of the hole down the barrel, it might be measured in the lands or grove.

 

[Foxyboy43]

Hmmm.
Whilst there are very narrow differences in specs. the 7.62x54R (Rimmed but often misquoted as “Russian”) is pretty much interchangeable with the Finnish 7.62x53R though I have seen “warnings” not to shoot a lot of 54s in your 53. When I first started shooting Mosins I found it very confusing - especially to read that the nominal bore for the Russian Mosin was anywhere between .310 and .314 whilst the Finn was normally a true .308 as they had been rebarrelled by the Finns. The common practice was to slug the bore with an old lead fishing weight to determine actual dimensions.
This is from Wiki:-
The Finnish commercial ammunition manufacturer Lapua does not make a difference between the 53R and 54R, but produces cartridges that will function in weapons chambered for either one.
The Russian ammunition maker Barnaul states that Russian cartridges marked 7.62×53 are the same as 7.62×54. From their web site: "Some hunters have been confused because there have been varying marking on the package, case bottom and stamps: 7.62×53: 7.62×53R: 7.62×54: 7.62×54R. This happened because the 53.72 mm case length was rounded off differently in various countries. After Russia became a member of the European Permanent Coordinated Commission, the final name - "7.62×54R" - of the cartridge was accepted. “.
Plenty enough there to confuse any aspiring Mosin owner - certainly based on the two WW2 Russian Mosins I shoot the chambers are “generous” to say the least so using Finn 53 spec ammo is never going to be an issue.
Regarding the legality of “mixing” rounds as far as I recall the interpretation turns on what the firearm was designed and manufactured to accept and shoot (assuming no… err…. “changes” have since taken place) rather than what the cartridge case states. An extreme example can be seen on the toob where some individuals load and fire 50 cal. rounds in a 12g shotgun - doing this doesn’t make your favourite Baikal or Purdey an anti-aircraft gun though I believe it is illegal - unless of course you have doing so on your fac….
As an aside I quoted the 12g/50cal example to our licensing people when they refused to take a bequeathed rook rifle off certificate as after testing by their “expert” it accepted, chambered and fired a .38 bullet - I quoted the “designed and manufactured to accept” bit of the legislation and the 12g/50 cal example and they took said rook rifle off certificate - albeit reluctantly….
As a further aside, during a particularly boring Covid lockdown day I started fiddling experimenting with some .243 brass, the parent case of which is .308 Winchester. By interim resizing with a 6.5x55 SE die and finishing with a .308 die I turned out .308 cases which of course are stamped .243 but clearly will no longer chamber in a .243 rifle (which is really lucky as I don’t have one anyway).
Now if my local Firearms Officer was sharp enough to notice that I had .243 brass and started to make a fuss then a simple measurement would I imagine spoil their day - unless someone else knows different…..

 

[castbullets.co.uk]

Calibre is the size of the hole down the barrel, it might be measured in the lands or grove.

Yes, however your (and my) FAC states “CALIBRE METRIC OR IMPERIAL” when listing ammunition and in my case certainly lists the cartridge as well as the calibre. For example, mine says “6.5mm Creedmoor” and “.338 Lapua Mag”. This is in line with the guidance to FLDs of course.

So for those suggesting the head stamp is irrelevant, when an FEO (or worse, a Police officer without any firearms knowledge) is looking at an ammo case full of cartridges stamped 7.62x53R and your FAC says 7.62x54R, what is going to give you the comfort that you’re not going to lose your FAC and liberty because of it?

 

[cjm1066]

So if I resize 308 to 260 Remington I have the wrong headstand, that is only a problem if the FEO don't listen.

 

[ashray]

i have a lot of 308 cases necked down to 243.its never been an issue.

 

[Jura]

Back in the day, I asked for a variation for a 275 Rigby or a 7x57 Mauser.
They said I could only have one or the other, bearing in mind that they are both the same calibre with different names.

 

[M@tt]

The forms all state calibre but what they want is cartridge size. There was a HO circular that went out a while back asking FLDs to stop issuing FACs with a broad calibre option.

However in this case I would say what is written on the cartridge is irrelevant, as long as the cartridge is the size you are allowed to possess then it'll be fine.

I cannot see where this would be an issue without something much worse happening first.

There is a risk of being too pedantic. I know some places won't sell eg, 223 ammo to you if you have only 556 on your FAC and I know one range shop won't sell 22wmr on a 22rf slot as "RF means LR" even thought the wmr rifle is written down as 22RF.

 

[Jura]

There is a risk of being too pedantic. I know some places won't sell eg, 223 ammo to you if you have only 556 on your FAC and I know one range shop won't sell 22wmr on a 22rf slot as "RF means LR" even thought the wmr rifle is written down as 22RF.

I had a similar issue with my FAC which has 275 Riby on it and an RFD would not sell me 7x57 Ammunition.
Solution; load your own.

 

[Heym SR20]

I don’t there is a legal definition of calibre or cartridge per se in the Firearms Legislation.

Cartridge designation of adopted cartridges is defined on the CIP drawings for each cartridge and given that the UK is a signatory to CIP I would suggest that would be the basis for an argument.

However whilst I can easily resize 308 brass down to 243 and make 243 Winchester ammunition, I can foresee huge embuggerance factor if you got stopped for a dodgy tail light and over zealous police sergeant starting looking at all your ammo. Why 308 loaded ammunition when you FAC says 243 - oh no its not, oh yes it is etc etc.

My reckoning, unless you really have to, just use appropriately head stamped brass.

 

[castbullets.co.uk]

I don’t there is a legal definition of calibre or cartridge per se in the Firearms Legislation.

Cartridge designation of adopted cartridges is defined on the CIP drawings for each cartridge and given that the UK is a signatory to CIP I would suggest that would be the basis for an argument.

However whilst I can easily resize 308 brass down to 243 and make 243 Winchester ammunition, I can foresee huge embuggerance factor if you got stopped for a dodgy tail light and over zealous police sergeant starting looking at all your ammo. Why 308 loaded ammunition when you FAC says 243 - oh no its not, oh yes it is etc etc.

My reckoning, unless you really have to, just use appropriately head stamped brass.

Indeed. And in the case of 7.62x53/54R, there are CIP drawings for both just to make things even more tricky to argue.

I’d far rather use Lapua brass than the alternatives of either relatively poor PPU brass or paying over the odds for Peterson which isn’t as good as Lapua. That said, I’d prefer not to go to prison over it either. What I might well do in my specific personal case is ask my FEO to put both cartridges designations down just in case…

 

[shakey jake]

Has any one had their home loads checked? I never have.
I really think you are worrying about a problem that doesnt exist

 

[Heym SR20]

Indeed. And in the case of 7.62x53/54R, there are CIP drawings for both just to make things even more tricky to argue.

I’d far rather use Lapua brass than the alternatives of either relatively poor PPU brass or paying over the odds for Peterson which isn’t as good as Lapua. That said, I’d prefer not to go to prison over it either. What I might well do in my specific personal case is ask my FEO to put both cartridges designations down just in case…

Probably sensible. Have a look at the two drawings- look at the dimensions and are they within tolerances of each other. I know that the 275 Rigby is just slightly smaller in case and shoulder length than the 7x57 for example, but ammo is interchangeable unless you have max size 7x57 in a min size 275 chamber.

My suggestion is put your observations/ request in writing to the FEO so that he has it on file, but equally what ammo / cases are readily available. I do have 7x57 / 275 Rigby on mine.

 

[Jura]

Has any one had their home loads checked? I never have.
I really think you are worrying about a problem that doesnt exist

Nope, I even asked my FEO if he would like to see my reloading bench and equipment t; he wasn't interested in that.

 

[AlexD]

The forms all state calibre but what they want is cartridge size. There was a HO circular that went out a while back asking FLDs to stop issuing FACs with a broad calibre option.

However in this case I would say what is written on the cartridge is irrelevant, as long as the cartridge is the size you are allowed to possess then it'll be fine.

I cannot see where this would be an issue without something much worse happening first.

There is a risk of being too pedantic. I know some places won't sell eg, 223 ammo to you if you have only 556 on your FAC and I know one range shop won't sell 22wmr on a 22rf slot as "RF means LR" even thought the wmr rifle is written down as 22RF.

I don't have a .308 on my FAC, but do have .308 cases and bullets, because they are the basis for various other calibres which are on my ticket.
This means I have a few hundred rounds stamped .308 which are not for 0.308s, and do not have .308 bullets., and other rounds which have 0.308 bullets in a variety of case stampings, that are not deemed to be a 0.308.
I also have boxes of .308 bullets, which are used in cases that go into my K31 (7.5 x 55mm), and are shot out of the K31. However, they are not technicallly .308 rounds, they are 7.5 x 55 rounds, regardless of the base (head) stamp and the bullet fitted being 0.308.
The FAC added 0.308 ammo to my FAC, even though I have no .308 rifle, to avoid anyone getting over-zealous following the recent change in law about owning ammo.
My FEO did have a look at the loading bench, in a nice and friendly way.

 

[Yorkie]

Has any one had their home loads checked? I never have.
I really think you are worrying about a problem that doesnt exist

Hi. Only check i have had, was an FEO who was not aware of the .22BR cartridge i used. He was genuinely interested as it was a new to him cartridge. I showed him a case which obviously stated 6BR on the headstamp. I just explained i had to use 6BR as the parent case. He was genuinely interested and not snotty in anyway. No issues. I suggested they keep the book 'Cartridges of the world' in the office to help them on any more unusual cartridges or wildcats.

 

[shakey jake]

Hi. Only check i have had, was an FEO who was not aware of the .22BR cartridge i used. He was genuinely interested as it was a new to him cartridge. I showed him a case which obviously stated 6BR on the headstamp. I just explained i had to use 6BR as the parent case. He was genuinely interested and not snotty in anyway. No issues. I suggested they keep the book 'Cartridges of the world' in the office to help them on any more unusual cartridges or wildcats.

so no issue with head stamp