Bullet comparator, new to reloading.

maxwell

Well-Known Member
If possible guys a little help. Just started reloading in 243 and 270.
Made up a batch of each but hav'nt had the chance to test them yet.

Reading various books etc a comparator is mentioned, however some people also advocate not using one??
The area of doubt I have is some batches of rounds measure 0.087" difference others 0.007" difference, all with the bullet seating die set the same (measured overall with a set of calipers).
The 0.007" difference i'm not to worried about at this stage but the difference in the rounds is a little frustrating.

Having looked at comparators I have no idea which to go for, so a point in the right direction would be helpful :).
 
Hi Maxwell,
I use the hornady (ex stoney point) comparator, it comes as two parts, the holder and the bushings which comes in different calibres, however if you are using different calibres you will sharp end up with the same amount of holders as bushings, the holder with bushing attached fixes onto a standard calliper, either digital or analogue. This allows you to accurately repeat the length of you assembled cartridges and or adjust the length in relation to the throat of your chambers. The benefit of using a comparator as opposed to just a calliper is that it measures from the ogive of the bullet rather than the tip, the majority of tips on heads especially soft points are visibly inconsistent.
If you google bullet seating depth, there are various videos showing a comparator in use.
 
i use a comparator but have never heard of a reason not to use one.does anyone know of such a reason
matt
 
i use a comparator but have never heard of a reason not to use one.does anyone know of such a reason
matt
matt. I was given the Straight L-N-L- O.A.L. Gauge by someone who didn't know how to use it and didn't want it cluttering up his reloading bench. So I didn't look a gift horse in the mouth. Rgds JCS
 
they are good if you want to get a more true measurement of your loads. all bullets will have a difference some more then others if you measure to the tip this is where it shows.

the reason people measure to the ogive is because its a more consistant measurement around that part of the bullet then the tip.

a good way to help with run out i was told is when you seat your bullet half seat it then turn the case on the shell holder at 180 then seat it the rest of the way.

ive tryed this and it does seam's to help. some bullets are more consistant then other. i have noticed when loading vmax v blizkings the blizkings seam to come out consistant length with the odd one abit different.

the vmax some are 2 to 4 tho more then the length i want. nothing in the real world but a target shooter wouldnt be happy with that.

the the load and lock guage is for you to work out the col of your chamber. not to measure the ogive length
 
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Thanks for the direction, will order the hornady comparator.
Is it possible that the seating die is making a difference to the length??
 
I bought a comparator, .243 comparator insert, .243 modified case and hornady OAL gauge this week from reloading solutions. The cost was £69 for next day delivery before 1300hrs. Very easy people to deal with, friendly and happy to assist.
 
if you have set the die up right and locked the ring off it shouldnt move at all. its more then likely inconsistant bullet heads. some batches are known for it. i no its a pain but have a look at the box of bullets and just measure the heads with your calipers and your see what i mean
 
As mentioned, if your seating die is properly locked in place it's unlikely to be that.
You don't mention what bullets you are using but it is highly likely there is quite a bit of variance in the lengths of these bullets. Even Lapua Scenar and Sierra Match King show suprising amounts of variance in bullet length.

What is important is the length to ogive as this is where the bullet engages the lands. if the jump is excessively erratic then the results will be too.
I use the 2 part hornady comparator but I've also used a sinclair hexagon which looks like a nut which various holes in it. Both are good but the hornady attaches to micrometer.
 
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