Thread: Inaccurate Cartridges

Cant say I have seen too many 9mm or 45acp carbines that were super accurate although I guess it goes back to the ammo.

Someone will contradict me

Originally Posted by veitnamcam

Much is made recently of the inherent accuracy of having a short fat powder column. wsm saum br etc
Yet many get great results out of 30-06/6.5 etc

I have no experience to quantify the differences but am interested where this thread will head.

@veitnamcam,

The 30/06, despite of any long-powder-column disadvantage if such exists, will have one advantage from its long case length: A LONGER cartridge will more readily line up with the bore axis, which in turn helps its bullet engage with the rifling on-axis.

A bullet which is perfectly balanced on the rifling axis is less like a corkscrewing aerobat before its spin eventually stabilises it at some point of its corkscrew. This is why some large groups often describe circles (with the centre less densely holed, rather than a uniform peppering of holes covering the entire area of a circle).

Originally Posted by 300CALMAN

Cant say I have seen too many 9mm or 45acp carbines that were super accurate although I guess it goes back to the ammo.

Someone will contradict me

@300CALMAN,

From memory, the Sterling L2A3 9mm SMG (WW2 Patchett SMG derivative) fired from an open bolt. And it was required to be able to hit within a 10 cm circle at 200 metres, obviously in semi-auto mode. That is <2 MOA. This is not super accuracy, but it is superlative accuracy in a 9mm SMG. About as much as anyone should ever hope to get out of the 9x19mm. Someone please correct me.

Originally Posted by Cordite

@veitnamcam,

The 30/06, despite of any long-powder-column disadvantage if such exists, will have one advantage from its long case length: A LONGER cartridge will more readily line up with the bore axis, which in turn helps its bullet engage with the rifling on-axis.

A bullet which is perfectly balanced on the rifling axis is less like a corkscrewing aerobat before its spin eventually stabilises it at some point of its corkscrew. This is why some large groups often describe circles (with the centre less densely holed, rather than a uniform peppering of holes covering the entire area of a circle).

Yes but would be mitigated by close chamber dimensions.

I was hoping someone may have burnt a couple of barrels in a target rig with a long case and gone to a short and fat case in a apples with apples comparison.

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cant really say ive come across an inaccurate cartridge come across a few inaccurate rifles tho some could be fixed some couldn't ive come across fussy cartridges that in factory loads were crap but a little experimenting with hand loads sorted them 22 hornet springs to mind

Originally Posted by veitnamcam

Yes but would be mitigated by close chamber dimensions.

I was hoping someone may have burnt a couple of barrels in a target rig with a long case and gone to a short and fat case in a apples with apples comparison.

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@vietnamcam

Apples for apples, I was thinking of long vs short cartridges, both in military loose chambers. With the exact same tolerances employed, the longer cartridge will of course be more likely to sit on-axis. But how big that effect is for accuracy... who knows.

To help cartridges sit concentric with the rifling bore, some advocate putting a thin O-ring round the base of the cartridge, a couple mm ahead of the rim on rimmed cartridges or extractor groove on non-rimmed cartridges, to help keep the case body centered in the chamber. Helps ensure the bullet engages concentric with the bore. Of course this is also nifty if you reuse cases and that first shot fireforms the brass for your chamber, and only neck sizing from then on. To be completely obsessive, you'd also mark 12 o'clock on the rear face of the cartridge, in case the chamber is assymmetric, and from then always chamber it 12 o'clock up.

Originally Posted by Cordite

@300CALMAN,

From memory, the Sterling L2A3 9mm SMG (WW2 Patchett SMG derivative) fired from an open bolt. And it was required to be able to hit within a 10 cm circle at 200 metres, obviously in semi-auto mode. That is <2 MOA. This is not super accuracy, but it is superlative accuracy in a 9mm SMG. About as much as anyone should ever hope to get out of the 9x19mm. Someone please correct me.

Interesting, I thought it was a square foot at 100 yards, I have heard some comments to the effect that some 9mm pistols were considered quite accurate. Like the Luger, unfortunately it was apparently made with tight tolerances and struggled with eastern front conditions.

Originally Posted by 300CALMAN

Interesting, I thought it was a square foot at 100 yards, I have heard some comments to the effect that some 9mm pistols were considered quite accurate. Like the Luger, unfortunately it was apparently made with tight tolerances and struggled with eastern front conditions.

@300CALMAN, you are correct of course. Wikipedia states the requirement as "...sufficiently accurate to allow five consecutive shots (fired in semi-automatic mode) to be placed inside a one-foot-square target at a distance of 100 yd (91 m)." Still impressive for an open-bolt firer. Wonder how good an MP5 would do?

Originally Posted by Cordite

@300CALMAN, you are correct of course. Wikipedia states the requirement as "...sufficiently accurate to allow five consecutive shots (fired in semi-automatic mode) to be placed inside a one-foot-square target at a distance of 100 yd (91 m)." Still impressive for an open-bolt firer. Wonder how good an MP5 would do?

The K and baby Ks I played with were very accurate. Especially the SD versions.

The fellas that carried them for their role were scary fast and accurate with them.

Roller locking and fluted chambers iirc.
The L2 sterling smg was a pig of a thing.
I prefered the Aussie version of smg.



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Originally Posted by R93

The K and baby Ks I played with were very accurate. Especially the SD versions.

The fellas that carried them for their role were scary fast and accurate with them.

Roller locking and fluted chambers iirc.
The L2 sterling smg was a pig of a thing.
I prefered the Aussie version of smg.



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Never fired any of the above mentioned SMGs but had a play with them. Maybe it's because i a lefty but I thought the Sten handled better then the Stirling. MP5s are a work of art with more than a passing resemblance to a STG44.

Originally Posted by 300CALMAN

Never fired any of the above mentioned SMGs but had a play with them. Maybe it's because i a lefty but I thought the Sten handled better then the Stirling. MP5s are a work of art with more than a passing resemblance to a STG44.

Via the G3, you really see the Sturmgewehr-44 / StGw-44 resemblance there, especially with the older, wooden stocked G3.

StGw-44:

CEAM Modele 1950 (french manufactured gun, derived from StGw44, by emigrated German designer:

And the H&K G3:

The G3, sex on a stick!

Originally Posted by Marty Henry

The G3, sex on a stick!

Absolutely. A mate had a low mileage G3 20 years ago & still regrets to this day ever selling it.

The MP5 is sexy too. I've put about 120+ rounds through one on full auto & 3 shot burst, very accurate.

Originally Posted by Mathias

Absolutely. A mate had a low mileage G3 20 years ago & still regrets to this day ever selling it.

The MP5 is sexy too. I've put about 120+ rounds through one on full auto & 3 shot burst, very accurate.

@Mathias,

Do you recall what sort of accuracy did you get out of the MP3 on semi-auto?

Originally Posted by Cordite

@Mathias,

Do you recall what sort of accuracy did you get out of the MP3 on semi-auto?

Hi Cordite, no I don't recall actually putting many through in semi. I was more interested in 3 shot burst & full auto and I was at an indoor range in Charlotte North Carolina.
This image is of one of my targets set at 20 yards, mostly on auto.