case gauges / bullet comparators
- Thread starter mtnbkr
- Start date
MTNBKR,
+1 on the Sinclair tools. FYI Only buy 1 type of bullet comparator. Never use one bullet comparator to "check" another comparators accuracy. They are all DIFFERENT not wrong! Just slightly different dimensionally even from the same manufacturer. Same goes for bump gauge inserts used with dial calipers like Hornady and Sinclair. Both inserts will interchange in the inset bodies but that's where the similarity ends.
Take care!
Phil Hoham
Berger Bullet Tech
+1 on the Sinclair tools. FYI Only buy 1 type of bullet comparator. Never use one bullet comparator to "check" another comparators accuracy. They are all DIFFERENT not wrong! Just slightly different dimensionally even from the same manufacturer. Same goes for bump gauge inserts used with dial calipers like Hornady and Sinclair. Both inserts will interchange in the inset bodies but that's where the similarity ends.
Take care!
Phil Hoham
Berger Bullet Tech
A skilled reloader that can use a dial caliper will never get bored.
There are not many tools I do not have, I do not find the modified cases convenient, I want a case that holds the bullet because I use the case as a transfer when adjusting the seating die. The transfer eliminates the need for the OAL gage. I have the Hornady/Sinclair tool and modified cases, for me it is not necessary.
I determine the length of the case from the shoulder to the head of the case because my chambers may not be SAAMI spec. and my chamber length may not agree with the length of the modified case from the shoulder to the head of the case.
I drill the flash hole/primer pocket out on a case with good bullet hold, I seat a bullet then chamber the test case without the bolt. After chambering the test case I push the bullet out of the case until it hits the lands. The test case tells me the length of the chamber from the bolt face to the lands. And I know the diameter of the lands at the bullet contact. When adjusting the bullet off the lands I use the test case to zero the seating stem. After zeroing the height of the stem above the seating die I use the dial caliper to seat the bullet 'off the lands', this method turns all of my seating dies to micro adjust.
I have micro adjust RCBS type seating dies, they are nice, my favorite feature is the alignment between the bullet and neck of the case.
F. Guffey
I recently purchased the Sinclair insert comparator from Brownells for .30
Thing is too big.
The comparator hit the case on every piece of loaded .308 ammo I have from my hand loads to Federal Match loads. Only about 1/8" of the base showed on Berger 115s, I might work on a 200ish grain bullet.
It is a useless piece of junk. If you buy a comparator, don't buy the Sinclair.
Just take five unsized fired cases, start what ever bullet into it that you want to load by hand. Gently put it in the chamber and gently close the bolt. Very gently extract and measure from tip to base, average all 5. You will find that any quality bullet is extremely consistent (be careful with lead tips), and we don't care about non-quality bullets having consistent seating into the lands. Adjust your seating die and your done.
Thing is too big.
The comparator hit the case on every piece of loaded .308 ammo I have from my hand loads to Federal Match loads. Only about 1/8" of the base showed on Berger 115s, I might work on a 200ish grain bullet.
It is a useless piece of junk. If you buy a comparator, don't buy the Sinclair.
Just take five unsized fired cases, start what ever bullet into it that you want to load by hand. Gently put it in the chamber and gently close the bolt. Very gently extract and measure from tip to base, average all 5. You will find that any quality bullet is extremely consistent (be careful with lead tips), and we don't care about non-quality bullets having consistent seating into the lands. Adjust your seating die and your done.
BoydAllen
Gold $$ Contributor
Personally, having tried the Sinclair tool, I prefer the Hornady "headspace gauge" as well as the attachment for measuring off of bullet ogives (sometimes referred to as ogive length checkers). I think that tools that use inserts that try to too closely approximate chamber throats tend to have consistency problems with long, high BC bullets, because of wedging. If one wants to look at bearing surface, I would think that using two properly aligned attachments on the same caliper would get the job done. Perhaps a custom alignment piece would be required.
joshua43214 said:
This may not work for him, if his fired cases don't have enough spring back to gently hold a bullet.
I had my gunsmith make up a "comparator" with a piece of the barrel stub, using the throating reamer used in the gun. He also made a case gauge using the chamber reamer. Between the two, I can tell exactly where the rifling starts in my rifle, without needing to even look at the gun. This to me is the only accurate way to make a tool with any hopes of it being directly translatable to your individual rifle. Of course, it's only valid before you start shooting and experiencing throat wear.
Joe R
Gold $$ Contributor
Our very own Erik Cortina did a video about comparators. It's worth watching. https://www.youtube.com/watch?v=-ZWrr1_IPu8
Kindest regards,
Joe
Kindest regards,
Joe
Joshua43214,
The Sinclair bullet comparator inserts are made to work really with "over length" cartridges IE cartridges loaded with the bullet out twords the lands.This is due to a deeper hole before you get to the measuring surface that was added (by customer request) to stabilize the bullet better. For cartridge cases that "short bullets" say like a 52 grain BTHP in a .223 loaded to magazine length you run into your problem. The comparator bottoms out on the case mouth. The Hornady insert or the Sinclair "nut" would be a better choice with this shorter round. Joshua , were you loading a 300 AAC cartridge for an AR style rifle when you had the problem?
The Sinclair bullet comparator inserts are made to work really with "over length" cartridges IE cartridges loaded with the bullet out twords the lands.This is due to a deeper hole before you get to the measuring surface that was added (by customer request) to stabilize the bullet better. For cartridge cases that "short bullets" say like a 52 grain BTHP in a .223 loaded to magazine length you run into your problem. The comparator bottoms out on the case mouth. The Hornady insert or the Sinclair "nut" would be a better choice with this shorter round. Joshua , were you loading a 300 AAC cartridge for an AR style rifle when you had the problem?
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