sinclair comparator & 140gr hybrids and 140gr A-Max's issue...

[czar61211]

So I am using the sinclair comparator with a 6.5mm insert and was using it on the 140gr Hornady A-Max Factory Match ammo as a reference to see what they were loading their ammo to. Everything was fine. I then got to the 140gr berger hybrids and loaded them to the AICS mag length (2.800"...although I could probably loaded just a little bit longer than this) and put the comparator on it the the thing went all the way to the brass and seemed like it was still loose. So, I took aanother non-loaded bullet, put it on the comparator without the brass and the comparator stopped at what i assume is the bearing surface of the bullet (ogive). I took a sharpie, drew the line on the bullet, then compared it to the round I just loaded and saw that the "bearing" surface is just below the brass. The hornady a-max's had no problem and I know this has to do with the bullet geometry (secant vs. tanget). Has anyone else had this issue before? I think if I load the 140gr hybrid to ABSOLUTE max mag length, i might be able to measure the ogive with the 140gr hybrid loaded.

SINCLAIR INSERT STYLE BULLET COMPARATOR | Sinclair Intl

 

[boonewsm]

I've got the same setup with the Sinclair. Mine does the exact same thing on the 140 hybrids. I wonder if there is some tolerance issues with Sinclair or what. When i measured my lands in my factory dta barrel it's coming up quite different than other ppl on here measurements.


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[boonewsm]

I was at a buddy's the other night and I took mine with me and compared it to his Sinclair multi cal nut. It's definitely off I didn't right down exactly how much but it was enough. My 22, 6, and 30 cal seem fine but the 6.5 is definitely off.


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[SPAK]

Did you ever solve this? I'm finding the same with mine.

 

[OF&B]

Did you ever solve this? I'm finding the same with mine.

According to the Litz book, the Amax has a nose length of 0.689". The Berger reloading manual gives a nose length of 0.816" for the Hybrid.

To get the front edge of the bearing surface at the same position, the Hybrid will have to be loaded 0.127" longer than the Amax.

 

[1/2moamayhem]

I had the same problem with the Sinclair comparator in 6.5. It was unusable on some bullets. On other bullets it seemed to be stopping down on the bearing surface. I switched to the Hornady comparator and have had better luck. I think there was a thread about it a while back. I guess a number of guys are having issues with the Sinclair comparator.

Also just thought I'd mention that I've noticed some of the dimensions of the bullets I have can be quite a bit different than the published dimensions. I've got some 130 grain hunting vlds and some 130 grain target vlds. They are supposed to have the same dimensions but just looking at them the hunting bullets are considerable shorter and the bearing surface is considerable shorter as well. I measured them for kicks. I can't remember off the top of my head but I think they were close to 1/16" shorter than Berger and Litz's published dimensions.

They still shoot great. I wondered if the bc's would be a little different than published but they still seem to match up pretty good with the dope I've been using. No complaints.

What the hell might as well throw this out there to. I was jamming the 130 vlds .010. 5 shot groups were running about 1/2" at 100 yards. This rifle does better with other bullets so I thought I'd try the Berger jump test. Sure enough 5 shot groups are running in the mid 3's when jumping them 30 thou. (this is with a GAP built 6.5x47)