IOF .22 and IOF 315

The Doc · Post by **The Doc** » Wed Sep 12, 2007 6:40 pm

Is there a difference between the outer diameter or circumference between IOF .22 and IOF 315 barrels ? ( I do understand that both have different calibres).

regards,

RP.

Post by **cottage cheese** » Wed Sep 12, 2007 7:34 pm

ORTHOPOD";p="26520 wrote:Is there a difference between the outer diameter or circumference between IOF .22 and IOF 315 barrels ? ( I do understand that both have different calibres).

regards,

RP.

No idea- but knowing the way IOF works... they probably use the same steel stock for both to save thinking power and money perhaps

Post by **Mack The Knife** » Wed Sep 12, 2007 7:37 pm

CC,

What are the chances of the INSAS and IOF .22LR sporter sharing the same barrel? The latter has a very fast twist rate for a .22lr rimfire - 1 in 200mm (approx. 1 in 8").

Mack The Knife

Post by **cottage cheese** » Wed Sep 12, 2007 9:37 pm

Mack The Knife Bana";p="26535 wrote:CC,

What are the chances of the INSAS and IOF .22LR sporter sharing the same barrel. The latter has a very fast rate for a .22lr rimfire - 1 in 200mm (approx. 1 in 8").

Mack The Knife

Mack The Knife,

You'd probably right there and chances seem high.

IOFB is probably doing what the Soviets did in WWII- Since all basic infantry weapon types were bored in 7.62mm. Pistols, submachine guns, rifles and light machine guns etc. As a wartime expedient the Soviets basically bored and rifled(Other than Chambering) barrels for all these guns with the same machinery and stock.

IOFB's probably aping this in order to keep costs low (I suspect its more to do with the inability of the babus in charge to exercise their brains in managing inventory and stock

)

As you suggested the twist rate is a give-away - While older 5.56mm rounds performed well with 1:9/12, the newer heavier ones (SS109) work better with tighter twists (1:7).

Many so called 'universal' rifles have 1:8 as a compromise so that both ammo types can be used with reasonable efficiency.

As you'd already know almost all .22LRs have a twist rate of 1:16. As to why a .22LR rifle needs such a tight twist rate is suspicious

The Doc · Post by **The Doc** » Thu Sep 13, 2007 11:14 pm

GUYS,
Lemme take it further. How about the outer diameter or circumference of IOF .22, 315 , and the 30.06 being the same and the boring and the grooving be different???? I'd rest the INSAS.

best,
RP

shahid · Post by **shahid** » Fri Sep 14, 2007 3:22 am

They may be useing a single steel tube to form all barrels but the bore and grooving pattern will be different for all calibres and type of weapon.

The Doc · Post by **The Doc** » Fri Sep 14, 2007 7:14 pm

Shahid,
I agree, but that means different barrel thickness for different calibres, assuming that same steel tube is uesd.

best,

RP

Rudra · Post by **Rudra** » Fri Sep 14, 2007 7:38 pm

now pls dont drag 30-06 in this discussion because it is still in experimental conditions and above all i dont think that these people would ever be able to manage a RL cartridge like 30-06 as they have not yet been able to develop a proper ejector even for a PAG

shahid · Post by **shahid** » Sat Sep 15, 2007 11:37 am

Yes barrel thickness will be different, but that's all right as well as safety, QC and proof house parameters are met.

The Doc · Post by **The Doc** » Mon Sep 17, 2007 10:37 pm

The point I am arriving at is that is the barrel of the IOF .22 is heavier that the the rest of the .22s ( BRNO, winchester, Merlin etc). Has the heavier barrel got anything to do with the twist rate???
Last week I fired a Merlin .22 and my IOF .22 at a shooting range using the same ammo ( ELLY). THe Merlin had a louder bang !!! WHY??

Best ,

RP.

Post by **cottage cheese** » Mon Sep 17, 2007 10:41 pm

Last week I fired a Merlin .22 and my IOF .22 at a shooting range using the same ammo ( ELLY). THe Merlin had a louder bang !!! WHY??

Shorter barrel?

Post by **Grumpy** » Tue Sep 18, 2007 2:53 am

"Has the heavier barrel got anything to do with the twist rate???"

No.

I don`t know what the barrel diameter is on the rifle you`re talking about but heavy `bull` barrels are available for many .22lr rifles - the Ruger 10/22 for example is available with an almost 1" diameter barrel.

Post by **Mack The Knife** » Tue Sep 18, 2007 8:02 am

The diameter of my IOF .22lr barrel varies from 17.64 to 17.86 mm along its length. It is not a tapered barrel. The difference in measurement is probably down to the final finishing.

Now could someone with a IOF .315 rifle please measure the diameter of their rifle's barrel so that we can put this topic to rest.

Thanks.

Mack The Knife

shahid · Post by **shahid** » Tue Sep 18, 2007 12:41 pm

There are differences in diameter of the IOF .315 over the years. In 1970s it was some imported barrels, rebored. Now its local ( Indian ) procurement.

Very heavy barrels will be found in .22 LR rifles and some varmint bore rifles. The .22 LR with heavy barrels may be mostly target model rifles.

Varmit calibres need heavy barrels because a lot of rounds are fired say to kill a colony of prarie dogs or woodchucks or similar. It also makes the rifle tougher ( say in transport ) and all day carry.

However the grooving pattern or twist rate or lock to lock turn rate is not directly propotional to barrel thickness in any direct relation. There are various other ballistic factors going into the design.

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Indians For Guns

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