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Though CIP standards show dimensional differences between the two rounds, most of us seem not to worry much about those differences and consider the two to be generally interchangable. In the case of shooting 7.62x53R ammo (should one ever find any,) in a 7.62x54R weapon, there of course is no safety problem at all, since 7.62x53R is the smaller round in case length and bullet diameter, though accuracy might suffer.

My recent purchase of a 30 caliber Sinclair chamber length gage insert brought to light a fact about my M28-76 chamber which others may find useful. For those of you who aren't familiar with the tool, it is a turned piece of soft leaded steel the body of which is turned .308" and head turned .334" which is just small enough to enter the neck portion of a 30 caliber chamber but will stop when reaching the end of the chamber neck. It is seated to longer than usual maximum case length into a sized case which has been shortened below usual trim length by about 0.100". When chambered into a bolt action rifle, the insert is pushed into the case when it hits the end of the chamber neck and when removed, the assembly is measured to reveal the actual length of the chamber. Usually, chamber length is generous and all that one learns is that they may not have to trim their cases as much or as often. In the case of my M28-76, I learned that the chamber length is 2.111", which is longer than CIP maximum case length for 7.62x53R of 2.106", but shorter than the maximum allowable case length for 7.62x54R, which is 2.115"! This is even shorter than the CIP standard for minumum chamber length for the 7.62x53R which is 2.130".

This clearly illustrates the importance of trimming cases. The second case in the pictures below is a once-fired range pick-up Winchester (S&B) case that has been full length resized but not trimmed. It measures 2.122". When chambered in my M28-76, the neck was squeezed down considerably when cammed past the chamber end. This is the admonition we always read about in the reloading manuals but almost never see! By contrast, chamber length in my M39s and Soviet MNs is at least a generous 2.143"; leaving the case untrimmed would have had no consequences.

Several on this board have noted that their M28-76s seem to have tight chambers that will not accept most commercial ammo; mine is one of those. It has a barrel with a groove diameter that slugs .308", and will not chamber commercial S&B (or Winchester) 7.62x54R ammo due to the case head to shoulder dimension, not just the larger bullet diameter. It readily and easily chambers new Lapua brass, which is in fact headstamped 7.62x53R and starts out with a length of 2.085". It also accepts commercial Norma "7.62 Russian" ammo, which has .308" bullets and case dimensions in line with the Lapua.

Though some owners report that their M28-76s are barreled with M39 barrels with .310" groove diameter, mine seems to have been made to M28/30 specifications and I must conclude that it was really intended to shoot only 7.62x53R ammo, as are Finland's 7.62 TKIV 85 sniper rifles.

As a handloader, I have a couple of other observations: my Lee full-length resizing die sets case shoulders back adequately to chamber in my M28-76. Another owner of a "tight" M28-76 (I think it was Panzer) reported that his dies from other makers will not, without shortening the dies. The Lee case trimmer shortened that over-long case in the picture to 2.108" which will chamber but doesn't leave much leeway. The Lapua brass is so short that I doubt the Lee trimmer will ever touch it!

I hope those of you loading for your M28-76s or having ammo problems with them will find some of this useful.

Be well all,
Doug
 

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Thank you for a well written post on what I expected was the problem with the "short chambered" M28/76 rifles. I do not own one, but felt this was probably the remedy needed. I feel sorry for a novice reloader as it might seem a big and scary endeavor to deal with. It would of been for me when I started reloading! No hidden judgement on new reloaders, we are all new in the beginning, and human on top of that. You never should quit learning, no matter how long your at it.

How right you are about case trimming. All the aspects you mention are important both for safety and accuracy. When the shooter truly knows his chamber dimensions, you can stretch you case life out considerably, as well as fine tune your loads for accuracy. Unfortunately for some buyers it was a degree more than they wanted to go as far as reloading goes. I would of been disappointed if I had bought one to blast surplus ammo and not worry about all the safety issues. On the other hand I think if I had my choice I would want what you have, because I bet that will drive tacks and will be worth the effort in the long run. Again thank you for a well written and thought out post on this subject. Cheers, John.
 

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Sounds like the Stoney Point OAL gage, IIRC they were bought out by someone who has now 'simplified it' (cut costs of production). Now, if they are indeed short chambered and "unfired" condition as some may have been advertised, I'd bet a FDF Armorers Course project. Why short chamber a chamber for the heck of it ? Can any Finn's comment of the findings or their differnce of 54r vs 53r ?
 

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Many people forget that in the days of the 28's and 28/30's - the Finns had a treaty with the Russians that they would manufacture neither military rifles in 7.62x54R, nor 7.62x54R ammo... Many folks believe the difference between this and 7.62x53R is trivial... but I think this points out that the Finns were in fact abiding by the treaty.... While running 7.62x53R in a 7.62x54R might just end up with low velocity, poorer accuracy, and a very slightly blown out case... Going the other way around could be trouble.... especially in a rifle made for Accuracy - not for loose Battle tolerances

Thanks
 

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Many people forget that in the days of the 28's and 28/30's - the Finns had a treaty with the Russians that they would manufacture neither military rifles in 7.62x54R, nor 7.62x54R ammo... Many folks believe the difference between this and 7.62x53R is trivial... but I think this points out that the Finns were in fact abiding by the treaty.... While running 7.62x53R in a 7.62x54R might just end up with low velocity, poorer accuracy, and a very slightly blown out case... Going the other way around could be trouble.... especially in a rifle made for Accuracy - not for loose Battle tolerances
I am sorry to say, who ever gave you that information was wrong, there never was such treaty. What is generally known in Finland is that the Finns marked the caliber as 7.62 x 53R originally probably because at that time besides Russian 7.62 x 54R caliber there was also another existing (althought not popular) 7.62 x 54R cartridge with different dimensions originating from central Europe (Germany / Austria?). It is also worth noting that the original case length also actually in between 53 and 54 millimeter. Since Soviet and Finnish catridge development took their own paths for decades ultimately Finnish 7.62 x 53R and Russian/Soviet 7.62 x 54R ended up becoming two separate cartridges, which are interchangeable enought to that both cartridges work in most rifles chambered for either of them. However one should not automatically assume that both cartridges will work in any given rifle - especially so because both countries over time did several bullet designs which are not compatible with all used cartdridge chamber designs.

Early on Finnish-manufactured 7.62 x 53R ammunition was exactly copy of Russian 7.62 x 54R cartridge with M1908 spitzer bullet, but slowly differences started to emerge, with the Finns concentrating mainly in increasing shooting accuracy and in case of D166 bullet to suitability for long-range machinegun fire. At the same time the Soviets concentrated much more into making ammunition manufacturing more economical by going to cheaper materials. As a result Finnish industry kept using bullets made from lead and tombac (zinc-copper alloy) with brass cartridge cases and nowadays commercial Finnish 7.62 x 53R ammunition is for the large part with .308 bullets. At the same time Russian ammunition even if manufactured for commercial market tends to have bullets and cartridge cases made from mild iron/steel and wider bullets. Needless to mention the materials used don't behave the same way - for example mild steel bullets are not so forgiving when it comes to actual caliber of the bore as the bullets filled with lead. There was/is no real difference pressure-wise in between the two cartridges, but due to various bullet designs and gunpowder charges used with each bullet design there are quite a large differences between their ballistics. One example of this:
- Finnish 7.62 x 53R military issue cartridge with 13-gram/200-grain spitzer boat-tail D166 bullet from M/39 rifle: about 650 m/sec
- Finnish 7.62 x 53R commercial Sako Target cartridge with spitzer 8-gram/123-grain bullet from M/39 rifle: about 900 m/sec

Wikipedia has drawings showing C.I.P. maximum cartridge dimensions for both:
http://en.wikipedia.org/wiki/7.62×53mmR

Jarkko
 

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I am sorry to say, who ever gave you that information was wrong, there never was such treaty. What is generally known in Finland is that the Finns marked the caliber as 7.62 x 53R originally probably because at that time besides Russian 7.62 x 54R caliber there was also another existing (althought not popular) 7.62 x 54R cartridge with different dimensions originating from central Europe (Germany / Austria?). It is also worth noting that the original case length also actually in between 53 and 54 millimeter. Since Soviet and Finnish catridge development took their own paths for decades ultimately Finnish 7.62 x 53R and Russian/Soviet 7.62 x 54R ended up becoming two separate cartridges, which are interchangeable enought to that both cartridges work in most rifles chambered for either of them. However one should not automatically assume that both cartridges will work in any given rifle - especially so because both countries over time did several bullet designs which are not compatible with all used cartdridge chamber designs.

Early on Finnish-manufactured 7.62 x 53R ammunition was exactly copy of Russian 7.62 x 54R cartridge with M1908 spitzer bullet, but slowly differences started to emerge, with the Finns concentrating mainly in increasing shooting accuracy and in case of D166 bullet to suitability for long-range machinegun fire. At the same time the Soviets concentrated much more into making ammunition manufacturing more economical by going to cheaper materials. As a result Finnish industry kept using bullets made from lead and tombac (zinc-copper alloy) with brass cartridge cases and nowadays commercial Finnish 7.62 x 53R ammunition is for the large part with .308 bullets. At the same time Russian ammunition even if manufactured for commercial market tends to have bullets and cartridge cases made from mild iron/steel and wider bullets. Needless to mention the materials used don't behave the same way - for example mild steel bullets are not so forgiving when it comes to actual caliber of the bore as the bullets filled with lead. There was/is no real difference pressure-wise in between the two cartridges, but due to various bullet designs and gunpowder charges used with each bullet design there are quite a large differences between their ballistics. One example of this:
- Finnish 7.62 x 53R military issue cartridge with 13-gram/200-grain spitzer boat-tail D166 bullet from M/39 rifle: about 650 m/sec
- Finnish 7.62 x 53R commercial Sako Target cartridge with spitzer 8-gram/123-grain bullet from M/39 rifle: about 900 m/sec

Wikipedia has drawings showing C.I.P. maximum cartridge dimensions for both:
http://en.wikipedia.org/wiki/7.62×53mmR

Jarkko
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For a pratical example of this all you need to to is play with my rifle for 5 minutes with one round each of mil-surp 7.62x54R, Norma 7.62x54R, and lapua 7.62x54R. Mil surp will not chamber, period. The Norma will chamber with a good amount of pressure on the bolt. On both of these rounds there are stress marks on the shoulder or the cartrage within 1mm of the body. Lapua ammo, on the other hand, feeds like butter. Makes sense since it is marked as 7.62x53R.

On some mosins, particularly the 28/76, there is a difference between Finn and Russian standards.
 

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My M28/76 chambers russian surplus ammo perfectly as a regular Mosin would. No stress on chambering or ejecting the cartridges or marks on the primer at all . I haven`t shot it yet , but loading it and chambering dry is as smooth as my 91/30 Mosin . It has the "D" mark and the sweetest second stage trigger I have ever seen .
I was assured by the previous owner that the barrel was lugged and it is 0.310 . I guess that since it chambers surplus I would have no problem shooting it . Not sure if I should also try commercial match 182 gr Prvi Partisan , thou ... I heard that those have wider bullets , so if someone can give information on that as true or not , it will be much apreciated .
 

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My M28/76 chambers russian surplus ammo perfectly as a regular Mosin would. No stress on chambering or ejecting the cartridges or marks on the primer at all . I haven`t shot it yet , but loading it and chambering dry is as smooth as my 91/30 Mosin . It has the "D" mark and the sweetest second stage trigger I have ever seen .
I was assured by the previous owner that the barrel was lugged and it is 0.3910 . I guess that since it chambers surplus I would have no problem shooting it . Not sure if I should also try commercial match 182 gr Prvi Partisan , thou ... I heard that those have wider bullets , so if someone can give information on that as true or not , it will be much apreciated .
no problems at all with prvi match!









 

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im going to bump this thread as the question "will my 28/76 chamber surplus" comes up frequently, and the simple slug the barrel answer isnt the entire story. perhaps this should get a sticky?
I don't remember ever seeing someone ask "will my 28/76 chamber surplus". The usual question I see is "is it ok to shoot surplus ammo in my 28-76" and to that, myself and others have responded with "slug the barrel". Since many of the 28-76s are built on barrels with a .308 bore and most surplus ammo is .311, it makes sense to START there and at least figure out what you are dealing with. If you don't START with slugging the bore, you are just guessing. I agree there is more to it than just slugging the bore, but you have to start somewhere.

Also, it's pretty clear to most people that if it wont chamber a certain type of ammo, they're probably going to have a hard time shooting that ammo.
 

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I don't remember ever seeing someone ask "will my 28/76 chamber surplus". The usual question I see is "is it ok to shoot surplus ammo in my 28-76" and to that, myself and others have responded with "slug the barrel". Since many of the 28-76s are built on barrels with a .308 bore and most surplus ammo is .311, it makes sense to START there and at least figure out what you are dealing with. If you don't START with slugging the bore, you are just guessing. I agree there is more to it than just slugging the bore, but you have to start somewhere.

Also, it's pretty clear to most people that if it wont chamber a certain type of ammo, they're probably going to have a hard time shooting that ammo.
Hell, my 28 won't even CHAMBER standard surplus 54r. Bolt won't rotate more than 45 degrees on surplus without putting undue force on it and I've never tried completely closing it when experimenting on that for fear of doing serious damage to the bolt face/extractor.
 

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My M28/76 , as I said previously , chambers , closes bolt and eject the surplus as smooth as my 91/30 Mosin . No signs or feel at all of getting stuck , stress or primer compression at all ... I have done at least 40 times dry mode to loading the magazine with 5 rds and working the bolt to chamber and extract the rds and not a single problem . I also checked visually to see if the neck or shoulder on the rds was bruised or scratched , just in case ... nothing . This rifle has the "D" mark on the barrel . I think that the Finns enlarged the chamber on mine very well and the neck short problem is a non issue on this rifle and with a lugged result of .310" the surplus ammo, which is .311" is ok to shoot . I was concerned on the Prvi Match 182gr ammo , but it seems that it is also .311" like the surplus , so I am very happy about it and I am ordering some boxes ot it . I will be taking it to the range next week or so for the first time . I am sure that this thing will be amazing to shoot. I have polished both the receiver and the bolt and it works almost as smooth as my Savage 10FCP-5R ... well , not quite , but it has improved a lot and the bolt now is really smooth and works very nicely .
 

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My suggestion to anyone with a short chambered 7.62x54r 28/76 i.e. one that has a 7.62x53r chamber is to simply take a standard 7.62x54r chamber reamer place it in your rifle and length THE chamber to 7.62x54r. This takes about 45 mins. to do and you can still fire the short Finnish 7.62x53r and the longer standard cases. BUT you need to load your brass cases to what ever bore Dia. your 28/76 has! THIS in no way will harm the rifle but makes it easy to purchase the standard 7.62x54r brass cases and save time and money.
 
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