another 7.5 ar question

Leg said:
If that's the case than why does Wes state that the bullet doesn't complete a full revolution before leaving the barrel?
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Well i guess it depends on how you calculate barrel lenght...

if its calculated like in canada, with the chamber... Than its 7.5 inches - the lenght of a 556 casing, so about 2 inches, leaving you with 5.5 inches of groves.

That angle difference in the grooves makes a big difference in that short time period to stabilize. Not to mention polygonal rifling in the works that help a lot.

Lets just say that for shooting with interesting results at any short distances -300, 1in7 would be better for the use. 1 in 9 is ok, it stilll sends the bullets forward, but as i mentioned, the heavier weight bullet is seriously suggested for short barrels, as you would need every aspect of stability needed:

Short = less speed but less time to stabilize, thus needing a heavier to compensate for the speed, but only up to the point that the barrel can stabilize it . Think of it as a rotational diagram.


As mentionned in my previous post, i got some keyholes @ 50 and 100 with a pletora or ammo in the 1 in 9 , m885, m193 even tried the 52 gr SMK and 69 and 77 SMK 62 gr was the limit for anything decent... 52 gr was laughable 55 gr was the best result...
 
greentips said:
Wes Grant can do whatever he wants - he knows his stuff and his uppers work.
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No one said that he doesn't know his stuff. Probably didn't help that the link was for his own ad, hardly objective. A comparison of various 7.5" uppers would be nice.

Kako, thanks for the explanation, wasn't really thinking straight and forget about the space the chamber eats up. Your explanation makes sense, still be nice to get a few uppers together for a side by side comparison.
 
If you use a carbine barrel and relocate the gas port, you'll need a gas block that fits, most carbine are profiled away at that point.

Why not a 10.5"? It's a LOT more effort for the extra 2".
 
dangertree said:
If you use a carbine barrel and relocate the gas port, you'll need a gas block that fits, most carbine are profiled away at that point.

Why not a 10.5"? It's a LOT more effort for the extra 2".
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I second that.

Also, 7.5" is awefully dirty and all the parts take a good beating.

On the other hand, it is very loud and I like the fire ball it spits out....even during the day.
 
Keep your eyes on the EE section and maybe the local stores in your area and the above sponsors.

There is another thread here which tells why its getting harder and harder to get the shorter A/R (and almost all other A/R stuff) in Canada now.

Good luck.
 
Question... So I have the 7.5" barrel so I'm expecting the gas port opening to be drilled the right size.
It came with a four rail gas block and I want to replace it with a low profile instead.. now, do I have to worry about the hole size in the gas block or are they all the same at that point?

I've been looking but I don't see any notes on any gas blocks mentioning hole sizes.
 
CJacob said:
Question... So I have the 7.5" barrel so I'm expecting the gas port opening to be drilled the right size.
It came with a four rail gas block and I want to replace it with a low profile instead.. now, do I have to worry about the hole size in the gas block or are they all the same at that point?

I've been looking but I don't see any notes on any gas blocks mentioning hole sizes.
Click to expand...

All the same... just need to line up properly.
 
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