cz 527 COL

[quicko]

quick question for any one that loads for a cz527 in .223. i was helping a friend to load a couple of 60gr vmax  test rounds for his rifle this evening and using oal gauge and comparator etc the oal - 0.030 off the lands was 1.845 ". does this seem short to anyone else shooting this rifle.  i load for a few rifle calibers including a sauer .223  but  when i was adjusting my lee seating die the min oal i could get down to was 1.855".  the winchester factory rounds he has been shooting were from memory around 1.846" or something similar.

 

thanks Keith 

[Grum87]

My 527 carbine was very, very short in the throat. Even factory ammo jammed right into the lands. Never caused me any issues though, it shot very well. You're limited in cartridge length by the magazine also.

[Andrew]

I load to specified OAL so I won't be of any help.....

Great rifle....~Andrew

[gunner]

Hi kieth , your after good accurate re-loads right ? So they could end up shorter or longer , find the best COL / then its Where it is - the rifle ammo likes what it likes . Without sounding condensending .  Is there much room left in the mag ? Once you have found the accuracy node ? Good luck with it there cracking little rifles.

[quicko]

Thanks for the replies . The mag has room left for longer oal so I guess we will see what they shoot like. 

 

Keith 

[henryo]

Interesting as I've found factory barrels in general seem to have excessively long throats and I can't get anywhere near the lands with the bullet still having a good amount of bearing surface contact with the case neck. I think they do it to reduce the possibility of bullets being jammed in to the lands and producing pressure spikes with variable factory ammunition / dodgy reloads. You can still get very good accuracy with a long jump to the lands e.g. 100 thou or more but some bullets are more tolerant than others.

I imagine the 60gr V-max is the classical tangent ogive and puts it fairly towards the tip hence shorter coal to lands. If you tried something like the 53gr v-max it would possibly work out longer.

I would try at 1.855" as 20 thou is still enough tolerance that one won't end up touching the lands due to bullet variation. You probably won't notice a difference in accuracy anyway.

[VarmLR]

The COAL with my 527 and 60gr Vmax for 10 thou off was 2.254 on the original barrel.  I have since rebarrelled mine as the original throat was worn though.  My new barrel is throated to accept 77gr bullets and the COAL for 60gr Vmax allowing 10 thou jump is 2.243.  1.845 seems very short imho as a COAL.  If you mean that is the measurement to the ogive using a comparator, then that isn't the COAL, its simply a comparator measurement to an arbitrary point on the ogive and what that distance is depends on the comparator used.  My Hornady comparator gives a measurement to ogive of 1.856" when COAL required is 2.254 so your 1.845 seems about right for the standard factory barrel.

[RobertH]

My 1:9" 527 shoots 60gr v-max (and in fact any bullet) really well only when the bullets are 002" to 003" into the lands, The Hornady comparator reading is 2.880”, and the COAL of a completed round comes out at around 2.278”. Was using CFE 223 and H4895, now on Viht N133.

[RobertH]

Me again....

Just re-read your post Varm, and I'm certainly not taking issue, but I wouldn't say the comparator measurement was from an arbitrary point, I am led to believe it is from where the ogive starts, i.e. where .224" stops and the curve begins. What Architects might describe as the springing point of an arch. 

[snakeman]

In my experience with these rifles virtually no absolute COAL measurement was required. They shot just about anything they were fed with ease, within the standard .223 seating parameters

I'd say you'd be better off practising with what you deem it to shoot best with, rather than unnecessarily looking for a measurement that probably won't exist

I found 24.5g of N140 under a 55g SBK pretty much from the off, and never looked back...

If it helps in any way, the COAL in my 527 was '2.235'. I have no idea what the B/O measurement was, or of ogive to lands measurement... blah blah... as I really didn't care to measure because I knew I would not have been able to make any further improvement than 0.5moa at 100yds with a consistent 5 shot group

To me your 'measurements' seem dubious at best, so I'd check again... but then again, you know your rifle better than me ~shrugs~

ATB

 

 

[Andrew]

3 minutes ago, snakeman said:

In my experience with these rifles virtually no COAL measurement was required. They shot just about anything they were fed with ease. 

I'd say you'd be better off practising with what you deem it to shoot best with, rather than unnecessarily looking for a measurement that probably won't exist

I found 24.5g of N140 under a 55g SBK pretty much from the off, and never looked back...

If it helps in any way, the COAL in my 527 was '2.235'. I have no idea what the B/O measurement was, or of ogive to lands measurement... blah blah... as I really didn't care to measure because I knew I would not have been able to make any further improvement than 0.5moa at 100yds with a consistent 5 shot group

To me your 'measurements' seem dubious at best, so I'd check again... but then again, you know your rifle better than me ~shrugs~

ATB

 

 

All of this. I load to manufacturer's specified OAL. I measure the first two rounds out of the sizer and then stop measuring. I get half MOA from my little 223 carbine for 5 rounds. No fuss. No muss.~Andrew