303 to 308?
- Thread starter maxim08
- Start date
I was say yes, but I would use a late manufacture No 4 action.
The Indians did some No1's but, as I understand it, the steel was different in that action than the usual No1 steel.
The conversion done here in Canada was done at the Long Branch and usually consisted of a barrel change and a bedding job only. The .303 extractor was used and the .303 mag was used as a single loading platform.
Scott
Dycor Special Services
The Indians did some No1's but, as I understand it, the steel was different in that action than the usual No1 steel.
The conversion done here in Canada was done at the Long Branch and usually consisted of a barrel change and a bedding job only. The .303 extractor was used and the .303 mag was used as a single loading platform.
Scott
Dycor Special Services
There is a twelve shot 308 clip available . I have one on mine. There is an extracter made as well but it is easier and more reliable to just grind the groove where the extracter sits on the bolt and us the 303 extracter.
To get 308 (7.62 Nato) performance from a # 4 is easy enough, without changing the barrel and clip.
The case volume of the 303 case and the 7.62 Nato is identical, and handloading the 303 cases, using the 7.62 Nato, also called 308 Winchester, handloading data could not be easier
Also, most 303, .311 diamter, Lee-Enfield rifles will shoot the plentyful and ordinary .308 bullets with no ill effects on accuracyand velocity. If using the .308 bullets when reloading the 303 British, it is important to change the .311 expander with a .308 expander in the 303 British full lenght rezising die, for a proper and tight bullet fit in the 303 British cases.
Use only #4 Lee-Enfield rifle when using 308 Winchester (7.62 Nato) reloading data, instead of the 303 British reloading data.
The case volume of the 303 case and the 7.62 Nato is identical, and handloading the 303 cases, using the 7.62 Nato, also called 308 Winchester, handloading data could not be easier
Also, most 303, .311 diamter, Lee-Enfield rifles will shoot the plentyful and ordinary .308 bullets with no ill effects on accuracyand velocity. If using the .308 bullets when reloading the 303 British, it is important to change the .311 expander with a .308 expander in the 303 British full lenght rezising die, for a proper and tight bullet fit in the 303 British cases.
Use only #4 Lee-Enfield rifle when using 308 Winchester (7.62 Nato) reloading data, instead of the 303 British reloading data.
snowhunter said:To get 308 (7.62 Nato) performance from a # 4 is easy enough, without changing the barrel and clip.
The case volume of the 303 case and the 7.62 Nato is identical, and handloading the 303 cases, using the 7.62 Nato, also called 308 Winchester, handloading data could not be easier
Also, most 303, .311 diamter, Lee-Enfield rifles will shoot the plentyful and ordinary .308 bullets with no ill effects on accuracyand velocity. If using the .308 bullets when reloading the 303 British, it is important to change the .311 expander with a .308 expander in the 303 British full lenght rezising die, for a proper and tight bullet fit in the 303 British cases.
Use only #4 Lee-Enfield rifle when using 308 Winchester (7.62 Nato) reloading data, instead of the 303 British reloading data.
NOT a good idea - listen to Riflechair!
Well - Looking at the Lee Reloading manual, max charges using RE15, ACCUR 2520 as examples, are close to identical between the two calibres. However, for the same amount of powder, velocity and pressure are substantially higher for the 308 (50 CUP vs 43 CUP, 2645 fps vs 2515 fps)
This would leave me to believe that case volume is not the sole determinant for ballistics, perhaps case profile has an influence. So to get 308 performance out of a 303 case would require going well above the recommended max 303 load, to get to the required pressure and velocity.
I recall reading that Longbranch 308 conversions required the receiver and perhaps other crucial parts to be radiographed as a proof requirement. This would be in recognition that the stresses in these parts were now at a sufficiently high level that flaw induced cracking could occur.
Gents - I plan on expiring due to old age, not from a Lee Enfield breech failure. FWIW - I load all my Lee's at close to minimum loads.
This would leave me to believe that case volume is not the sole determinant for ballistics, perhaps case profile has an influence. So to get 308 performance out of a 303 case would require going well above the recommended max 303 load, to get to the required pressure and velocity.
I recall reading that Longbranch 308 conversions required the receiver and perhaps other crucial parts to be radiographed as a proof requirement. This would be in recognition that the stresses in these parts were now at a sufficiently high level that flaw induced cracking could occur.
Gents - I plan on expiring due to old age, not from a Lee Enfield breech failure. FWIW - I load all my Lee's at close to minimum loads.
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- Location
- Ft. Mac. Alberta
snowhunter said:To get 308 (7.62 Nato) performance from a # 4 is easy enough, without changing the barrel and clip.
The case volume of the 303 case and the 7.62 Nato is identical, and handloading the 303 cases, using the 7.62 Nato, also called 308 Winchester, handloading data could not be easier
Also, most 303, .311 diamter, Lee-Enfield rifles will shoot the plentyful and ordinary .308 bullets with no ill effects on accuracyand velocity. If using the .308 bullets when reloading the 303 British, it is important to change the .311 expander with a .308 expander in the 303 British full lenght rezising die, for a proper and tight bullet fit in the 303 British cases.
Use only #4 Lee-Enfield rifle when using 308 Winchester (7.62 Nato) reloading data, instead of the 303 British reloading data.
different bullet diameters, different cases, different max pressure specs,
different and VERY dangerous!!
I don't know who you are, but I remember telling myyself never to reply to any of your idiotic "grasscutter" posts.
I have to ,make an exception here, because what you are suggesting to the fella that asked the question is bordering on dissasterous.
Do everyone a favour and refrain from posting any more of this crap.
Just becuae a smaller bullet is going to be used in a larger bore( don't know what kind of "Performance" you are looking for!) doeesn't mean the pressures will be lower.
Cat
Maxim08,
Most gunshows seem to have a few Mark 4 .308 conversions for sale. Just check out the target shooter displays. From what I've seen the old target rifles seem to sell for less than the sights hanging on them. It is probably a cheap way to break into long range competition to see if you like it, but I don't know what else they are good for. That might be why they are so cheap.
Dogleg
Most gunshows seem to have a few Mark 4 .308 conversions for sale. Just check out the target shooter displays. From what I've seen the old target rifles seem to sell for less than the sights hanging on them. It is probably a cheap way to break into long range competition to see if you like it, but I don't know what else they are good for. That might be why they are so cheap.
Dogleg
- Location
- Ft. Mac. Alberta
They were actually pretty good rifles wheen the rules stated that military ammo had to be used.
The idea was the ammunition was jnot too conssistant as far as load pressure and bullet tension, so the No.4 action with ist's "springingnous" (tech term) compensated by minimizing the high pressure loads , and narrowing the ES with the lower pressure loads.
This resulted in tighter groups , as opposed to a stiffer action, the P14 for example, that would send the higher pressure loads faster because it would not
"give " as much.
Cat
The idea was the ammunition was jnot too conssistant as far as load pressure and bullet tension, so the No.4 action with ist's "springingnous" (tech term) compensated by minimizing the high pressure loads , and narrowing the ES with the lower pressure loads.
This resulted in tighter groups , as opposed to a stiffer action, the P14 for example, that would send the higher pressure loads faster because it would not
"give " as much.
Cat
I have handloaded and fired several tousands 308 Wichester (7.62 Nato) loads in my 303 British, #4 Lee-Enfield's, without any signs of any pressure, like flattened primers and sticky cases, and case life is at par with the normal 303 cases, when reloading with neck sized cases.
Most of the time, when handloading, I do use the plentyful .308 bullets, which are 0.003 inch smaller in diameter then the 303 bullets, which are .311 in diameter, and when reloading and firing the 303 British with .311 diameter bullets, using the 308 Winchester data, I have not experienced any complications like sticky cases or flattened primers either.
After slugging my 303 Lee-Enfield barrels, I found that the indside barrel diameters did vary from .306 inch to 309 inch, and thus, most of the time give, satisfactory accuracy when loaded with the plentyful .308 diameter bullets.
If a # 4 Lee-Enfield is safe and strong enough for a 308 Winchester (7.62 Nato) caliber convertion, I thererfore cannot understand the argument of why it would be unsafe to reload the exact same case capacities of 303 British and 308 Winchester (7.62 Nato), using the 308 Winchester reloading data ?
Most of the time, when handloading, I do use the plentyful .308 bullets, which are 0.003 inch smaller in diameter then the 303 bullets, which are .311 in diameter, and when reloading and firing the 303 British with .311 diameter bullets, using the 308 Winchester data, I have not experienced any complications like sticky cases or flattened primers either.
After slugging my 303 Lee-Enfield barrels, I found that the indside barrel diameters did vary from .306 inch to 309 inch, and thus, most of the time give, satisfactory accuracy when loaded with the plentyful .308 diameter bullets.
If a # 4 Lee-Enfield is safe and strong enough for a 308 Winchester (7.62 Nato) caliber convertion, I thererfore cannot understand the argument of why it would be unsafe to reload the exact same case capacities of 303 British and 308 Winchester (7.62 Nato), using the 308 Winchester reloading data ?
Well - As 303 and 308 load data are very close there is not much consequence. However, in you first post, you mention getting 308 "performance" out of a 303, as an alternative to rebarrelling in 308. This is where folks get their shorts in a knot - to do this requires loading beyond max charges, and exposing the pressure parts to levels well beyond design. Yes - 303's have been converted to 308 successfully at various factories, but steps were taken to ensure that the rifles could cope with the higher pressures.
- Location
- Ontario defense force (ODF HQ)
snowhunter said:To get 308 (7.62 Nato) performance from a # 4 is easy enough, without changing the barrel and clip.
The case volume of the 303 case and the 7.62 Nato is identical, and handloading the 303 cases, using the 7.62 Nato, also called 308 Winchester, handloading data could not be easier
Also, most 303, .311 diamter, Lee-Enfield rifles will shoot the plentyful and ordinary .308 bullets with no ill effects on accuracyand velocity. If using the .308 bullets when reloading the 303 British, it is important to change the .311 expander with a .308 expander in the 303 British full lenght rezising die, for a proper and tight bullet fit in the 303 British cases.
Use only #4 Lee-Enfield rifle when using 308 Winchester (7.62 Nato) reloading
data, instead of the 303 British reloading data.
I'm very sorry snowhunter but I don't care how many 308's you have fired through your Enfeild IT IS STILL VERY DANGEROUS!!!!!
IMHO posting a "it's ok to to shoot the wrong caliber shell through a rifle" statement should be grounds for a BAN!!!!
cosmic, I would be very interested in knowning what steps were taken to ensure that the # 4 Lee-Enfield was strong enough to handle the caliber convertion to the 7.62 Nato, beyond the simple change of barrels ?
It is my understanding that the Isaporo convertions of # 3 Lee-Enfields to 7.62 Nato, included stronger steel and better heat treatment.
To the best of my knowledge, British military convertions of the # 4 Lee-Enfields to 7.62 Nato caliber sniper rifles, only included barrel, extractor and magazine convertions ?
cpt. canuck, in what way would a 303 British, # 4 Lee-Enfield, handloaded with 7.62 Nato reloading data, be more dangerous, than a # 4 Lee-Enfield, converted to fire the 7.62 Nato cartridge ?
It is my understanding that the Isaporo convertions of # 3 Lee-Enfields to 7.62 Nato, included stronger steel and better heat treatment.
To the best of my knowledge, British military convertions of the # 4 Lee-Enfields to 7.62 Nato caliber sniper rifles, only included barrel, extractor and magazine convertions ?
cpt. canuck, in what way would a 303 British, # 4 Lee-Enfield, handloaded with 7.62 Nato reloading data, be more dangerous, than a # 4 Lee-Enfield, converted to fire the 7.62 Nato cartridge ?
snowhunter - refer to my first post for the answer to your question. As the LE receiver utilizes rear lugs, the complete receiver body is stressed, as opposed to just the receiver ring for most rifles.
Non destructive examination is now used extensively in the industry.. Also, I would suspect that the (retrofit) 308 barrels would enjoy better metallurgy ie higher yield KSI, better (tested) impact resistance.
Non destructive examination is now used extensively in the industry.. Also, I would suspect that the (retrofit) 308 barrels would enjoy better metallurgy ie higher yield KSI, better (tested) impact resistance.
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At Long Branch, receivers were tested (X-ray? magnaflux?) before they were approved for conversion.
Backthrust on discharge is determined by area of pressure application. .303 and 7.62 are not going to generate the same backthrust, even if pressures are the same.
If the same weight of powder is fired in a 7.62 case and in a .303 case, are the resulting pressures the same, or does the different shape of the combustion chamber result in different pressures?
Regardless of whether or not accuracy is acceptable, the smaller diameter .308 bullet is going to allow more gas blow by. This would reduce peak pressures. It would also increase gas cutting and erosion in the leade of the barrel.
Most Enfield barrels were produced under wartime conditions, from rough forgings, not from uniform barstock. Fatigue failures are rare, but have been observed in the UK, firing Mk.7 ball. As cosmic has pointed out, the 7.62 conversion barrels are going to be made from better steel, under more modern conditions.
The Ishapore rifles aren't conversions. In the UK, India and Australia, it was observed that receiver failure occurred if SMLE receivers were fitted with 7.62 barrels.
Official conversions were in 7.62x51. These cartridge cases are heavier and stronger than .308 or .303 ones. Operating pressures are higher in 7.62 and .308 than in .303. The cases are manufactured with designed operating pressures in mind.
I note in Sierra that the recommended maximum load of IMR064 is 48.2 gr. in .308 with a 150 gr. bullet, and 44.4 gr. in the .303, also with 150 gr. bullet. That is an 8 1/2% increase over the maximum recommended charge.
I have no doubt that you have fired your rifle as you have described. I question whether these practices can be recommended for others to use.
Backthrust on discharge is determined by area of pressure application. .303 and 7.62 are not going to generate the same backthrust, even if pressures are the same.
If the same weight of powder is fired in a 7.62 case and in a .303 case, are the resulting pressures the same, or does the different shape of the combustion chamber result in different pressures?
Regardless of whether or not accuracy is acceptable, the smaller diameter .308 bullet is going to allow more gas blow by. This would reduce peak pressures. It would also increase gas cutting and erosion in the leade of the barrel.
Most Enfield barrels were produced under wartime conditions, from rough forgings, not from uniform barstock. Fatigue failures are rare, but have been observed in the UK, firing Mk.7 ball. As cosmic has pointed out, the 7.62 conversion barrels are going to be made from better steel, under more modern conditions.
The Ishapore rifles aren't conversions. In the UK, India and Australia, it was observed that receiver failure occurred if SMLE receivers were fitted with 7.62 barrels.
Official conversions were in 7.62x51. These cartridge cases are heavier and stronger than .308 or .303 ones. Operating pressures are higher in 7.62 and .308 than in .303. The cases are manufactured with designed operating pressures in mind.
I note in Sierra that the recommended maximum load of IMR064 is 48.2 gr. in .308 with a 150 gr. bullet, and 44.4 gr. in the .303, also with 150 gr. bullet. That is an 8 1/2% increase over the maximum recommended charge.
I have no doubt that you have fired your rifle as you have described. I question whether these practices can be recommended for others to use.
cpt. canuck said:
Do you actually think he was saying he was shooting .308 ammo through his .303 brit? It's fairly clear to me he was saying that he loads .308 dia. bullets in his .303 (.311 dia.) which doesn't pose any safety concerns that I can see.
As far as loading any enfield action with hot .303, not something I would do. I load my P14 fairly hot after fire forming brass, but it's alot stronger action.
Witout doubt, the generous freebore of the 303 British, # 4 Lee-Enfields, also helps to reduce the peak pressure, when using and shooting with the 7.62 Nato reloading data, in the 303 British, # 4 Lee-Enfields ?
As mentioned earlier, I did slug my various # 4 Lee-Enfield's, and found that the indside bore diameter to be from .306 inch to .309 inch, that made the use .308 bullets accurate enough for most shooting applications. However it appears that I still have some accuracy problems when shooting the 220 grain, .308 diameter, Hornady bullets in my Jungle Carbine, using 30-40 reloading data. Something to do with the rifling twist and barrel lenght in the Jungle Carbine ?
Thanks for these very useful informations tiriaq and cosmic
As mentioned earlier, I did slug my various # 4 Lee-Enfield's, and found that the indside bore diameter to be from .306 inch to .309 inch, that made the use .308 bullets accurate enough for most shooting applications. However it appears that I still have some accuracy problems when shooting the 220 grain, .308 diameter, Hornady bullets in my Jungle Carbine, using 30-40 reloading data. Something to do with the rifling twist and barrel lenght in the Jungle Carbine ?
Thanks for these very useful informations tiriaq and cosmic
