Delta L problem

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Safarigent
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Delta L problem

Post by Safarigent » Mon Jul 16, 2012 8:44 pm

I was reading some stuff online and came across the Delta L problem.
I read and reread the wikipedia page.
Google and read some more.
But i havent been able to understand what it is.
I am actually confounded.
Can anyone explain this in laymans terms?
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Re: Delta L problem

Post by xl_target » Mon Jul 16, 2012 10:01 pm

There are two main ammunition standards organizations; SAAMI in the US and CIP in Europe.
For whatever reason, they have slightly different dimensions published for the same cartridge. So it is possible that a rifle with a chamber built to CIP standards might have problems with ammunition built to SAAMI standards (and vice versa).
On the other hand this oversize is a major problem with break action and combination guns, which are less common in the United States than in Europe, because correct cartridges cannot be loaded into correct weapons in the event ΔL was not considered during manufacturing. Break barrel arms will not simply close when the cartridges and chamber dimensions are not in concert. For this reason the chambers of break barrel arms are generally manufactured with reamers that take ΔL into account.[1]
Generally bolt-action and break barrel hunting rifles in C.I.P. regulated countries are not cut to the minimum C.I.P. chamber dimensions so this problem is mostly theoretical. The arms manufacturer SIG SAUER brands Blaser and Mauser are however known for hammer forging tight (but still C.I.P. conform) chambers in their Blaser R93 straight pull bolt-action and Mauser M03 bolt-action switch barrel rifles and some rifle owners reported ΔL problems with those rifles. These problems can also occur with other European made rifle brands.
It isn't a very common problem here in the US, at least when using chambers and ammo made to SAAMI specs. Consequently, it should not be a problem when using chambers and ammo made to CIP specs. It is only when you have ammo and chambers made to different specs (i.e. SAAMI ammo in CIP chambers or vice versa) that you might have problems.
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Re: Delta L problem

Post by Safarigent » Mon Jul 16, 2012 11:01 pm

So,
We in india should not import a gun from europe and ammo from the states and vice versa.
I guess thats what it bouls down to?
Or,
Not use european ammo in firearms made in the states and vice versa?
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Re: Delta L problem

Post by xl_target » Mon Jul 16, 2012 11:16 pm

Not necessarily.
There are plenty of people in the US who use European firearms with American ammo and have no issues whatsoever. The same is true with American guns and European ammo. For example; Norma, Sellier & Belliot, Fiocchi, etc. sells quite a bit of ammo here in the US and I 'm not aware of any complaints of this nature. It is possible that this might be a problem but it is not the norm. However, testing your gun with whatever ammo you use is always a good idea before you set out for a hunt. You want to do that anyway, to verify zero or to sight in if the ammo is something you have not used before.

Maybe Two Rivers can chime in here and let us know how common this problem is.
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Re: Delta L problem

Post by TwoRivers » Tue Jul 17, 2012 12:25 am

Not all that common. American chamber and ammo specs for rimless cartridges are such, that a maximum case and minimum chamber are really not compatible. Unless the action has great camming power, such as the older (military) bolt actions. So the problem is largely confined to European rifles without , or little, camming power, minimum chambers, and American made ammo. In any case, a cartridge that is difficult to chamber because of this presents no safety hazard. It can be a problem with European break-open guns chambered for rimless American cartridges.
Fortunately, American made cartridges are just about never at maximum dimension, and rifle chambers almost never at minimum. Though most of us here have probably come across a box of cartridges that required quite a bit of turndown pressure to chamber. Usually appears to happen with that original box with 19 cartridges, picked up for a buck or two at a gunshow.
To sum up, I wouldn't worry about it unless my gun were a European break-open chambered for a rimless American cartridge, or a Blaser Model R93. Then I'd make sure the cartridges chamber readily, before going after something that will bite back. Or a trophy hunt.
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Re: Delta L problem

Post by Safarigent » Tue Jul 17, 2012 8:28 pm

At makes sense.
So is this problem only limited to rifles?
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Re: Delta L problem

Post by xl_target » Wed Jul 18, 2012 12:46 am

This problem could occur any time you have a chamber and commercially produced ammunition.
However, it is rare. I have never experienced it.

I do have German, Czech and Italian handguns and have used multiple brands of US made and European ammo in all of them with out a problem. I wouldn't really worry about it.
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Re: Delta L problem

Post by TwoRivers » Wed Jul 18, 2012 2:41 am

Safarigent wrote:At makes sense.
So is this problem only limited to rifles?
Rifles chambered for bottle-necked cases. Cases based on the .30-06 and .308 Winchester.

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Re: Delta L problem

Post by Safarigent » Wed Jul 18, 2012 5:27 pm

Lovely,
This is something like experiencing a Dual hydraulic failure with both engines simultaneously falling off and your co-p having the fits at the same time!
Rare, but an ever present danger!
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Re: Delta L problem

Post by Grumpy » Tue Jun 18, 2013 3:50 pm

The only time I`ve experienced a Delta L problem was years ago with one US brand of ammunition in my Sauer 202 .308 win.
I know of Blaser K95s that have problems with some US ammunition in some calibres.
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Re: Delta L problem

Post by Safarigent » Tue Jun 18, 2013 8:27 pm

Grumpy would you please answer a few questions about your 202.
When you change barrels from .308 to .30-06 and vice versa, do you need a new bolt too? I am guessing you do, as the specs for the cartridges are different.
Secondly, one hears that sauer rifles and products are expensive in their segment. Is the quality difference so huge to justify the extra price?
Thirdly, what stock do you have on it?
Fourthly, i cant seem to find any aftermarket triggers for the S202. How good are the factory triggers?
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Re: Delta L problem

Post by Grumpy » Tue Jun 18, 2013 9:13 pm

You don`t need to change the bolt providing the case head fits the bolt head. There are groups of cartridges with the same sized head.
Sauer are good - no doubting that. A basic rifle can be bought quite inexpensively because they are built inexpensively and in very large numbers. The Sauers are high quality, built in comparitively low volume - compared to a Remington 700, Savage or CZ for example - and therefore cost more to make and more to buy. You can spend considerably more money on a rifle than the cost of a Sauer. Is a London Best gun `better` than a mass produced Beretta ? In some ways it is and if you can afford one and want one you would be prepared to spend the money.
Sauer triggers are very good.- - again, it`s part of what you`re paying extra for. You won`t find aftermarket triggers for European made guns .... except maybe for CZs .... although CZ have improved the trigger considerably
Mine was a 202 Elegance with the conventional half stock.
I sold it because I didn`t care for the .308 Win ..... and because I made a decent profit on the rifle.
Make a man a fire and he`ll be warm for a day. Set a man on fire and he will be warm for the rest of his life.
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Re: Delta L problem

Post by Safarigent » Wed Jun 19, 2013 9:52 pm

Point taken. Thanks for replying.
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Re: Delta L problem

Post by Grumpy » Wed Jun 19, 2013 10:02 pm

It wasn`t a 202 Elegance, it was a 202 Euro Lux.
Make a man a fire and he`ll be warm for a day. Set a man on fire and he will be warm for the rest of his life.
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