OAL for .223 68gr BTHP

[Old Tanker]

I have a Remington 700 XCR LR, .223, 1-9 twist. I have had success with 60gr including V-Max, Nosler Ballistic Tip (.536 group) and Sierra TMK. I just bought some 68gr Hornady BTHPs. When I use the OAL gauge, the bullet hits the the lands at 2.232. The Sierra TMK hits at 2.272. I realize TMK IS a long, skinny bullet but this is a little confusing. Hornady load data says seat the 68gr at 2.250 for service rifle. My service rifle is, in fact, throated for longer, heavier bullets. Does this mean my Rem 700 can’t chamber the 68gr? I don’t think I should push the bullet below the case neck.

 

[1lnbrdg]

2.250 is AR-15 magazine length. The Hornady BTHP's and the Sierra TMK's were designed to be very jump tolerant and to be loaded magazine length.

The Remington should handle them find at the 2.250" length but they can also be loaded longer for single loading like we do in the AR's with 80 gr bullets.

 

[Old Tanker]

What is interesting is that if I follow the Hornady directions by placing the bullet deep in the case, chamber the modified case then push the rod forward until until the bullet touches, I get a short measurement, 2.245. If I place the bullet shallow in the case, then allow the bullet to seat by pushing the rod back as the case chambers, I consistently get 2.301. Sort of the old method using a new tool?

 

[Texas10]

To get a precise measurement using the Hornaday tool, ignore the push rod, neck or FL size the modified case and seat your bullet long. Install it on the tool and slide it in the chamber with a firm push and retract. Any tendency to stick upon withdrawal indicates the bullet is in the lands. Continue seating the bullet gradually deeper until no tendency to stick. Make sure the barrel is clean for this test. Additionally, after sizing the case slide it into the chamber (as above) but without a bullet and make sure the case is not dragging on the chamber walls as this will give false indications of bullet contact with lands.

Controlling cartridge OAL is important for magazine feed concerns, but not for accuracy in your model 700. You should be measuring Case Base to Ogive (CBTO) with the Hornaday OAL gage. Just be aware that where the gage contacts the ogive is different than where the ogive contacts the throat/lands, so you can't use a dimension from one bullet and apply it to another different bullet for loading purposes. You have to measure each different bullet make/shape/weight.

223's are particularly tricky to test. 308's are dead simple. Apparently it's a diameter thang....

PS. I gave up on the Hornaday tool long ago and now tap my fully fire formed cases to fit a 3 piece cleaning rod (6-32), label and save the case/bullet combination as a tool for future reference.

I hope this helps.

 

[Old Tanker]

To get a precise measurement using the Hornaday tool, ignore the push rod, neck or FL size the modified case and seat your bullet long. Install it on the tool and slide it in the chamber with a firm push and retract. Any tendency to stick upon withdrawal indicates the bullet is in the lands. Continue seating the bullet gradually deeper until no tendency to stick. Make sure the barrel is clean for this test. Additionally, after sizing the case slide it into the chamber (as above) but without a bullet and make sure the case is not dragging on the chamber walls as this will give false indications of bullet contact with lands.

Controlling cartridge OAL is important for magazine feed concerns, but not for accuracy in your model 700. You should be measuring Case Base to Ogive (CBTO) with the Hornaday OAL gage. Just be aware that where the gage contacts the ogive is different than where the ogive contacts the throat/lands, so you can't use a dimension from one bullet and apply it to another different bullet for loading purposes. You have to measure each different bullet make/shape/weight.

223's are particularly tricky to test. 308's are dead simple. Apparently it's a diameter thang....

PS. I gave up on the Hornaday tool long ago and now tap my fully fire formed cases to fit a 3 piece cleaning rod (6-32), label and save the case/bullet combination as a tool for future reference.

I hope this helps.

Big help thanks. Your explained method is what I ended up doing. Will probably switch to cleaning rod method. I just couldn’t believe that the 700 throat was shorter than the 2.260 SAAMI, magazine spec that I use for my NM AR. Thanks for your advice