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12/6/2019 7:27:02 PM
Posted: 11/30/2016 11:48:56 AM EST
Walking around the shop today I saw three 6" pieces of a2 steel 1/2" thick. Thought they might be ok to use for targets. Mainly for a 20" Grendel at 300yards with factory amax. I have three round pieces so I gave two to my heat treat guy. Told him to do One full treat on and draw the other one down somewhere in the middle. Do you think they'll be ok to shoot? Going to dimple, penetrate or shatter? Not sure if I'll mount them as swingers or hang on a nail or something angled down some.
Link Posted: 11/30/2016 11:50:24 AM EST
[Last Edit: 11/30/2016 11:50:35 AM EST by Pavelow16478]
Tell him to temper to around a 500 Brinell Hardness Number and you'll be fine
Link Posted: 11/30/2016 11:59:58 AM EST
[Last Edit: 11/30/2016 12:00:13 PM EST by Pavelow16478]
More specifically, heat to 1775F then air quench them immediately temper at 1050F for 4 hours and let it cool in the furnace. That should give you properties awfully close to AR500.
Link Posted: 11/30/2016 12:04:34 PM EST
A2 is reasonably tough at 60Rc or so, better than D2 but I bet the hard one still shatters after a bit. The double drawn piece should be mid 50's that will be pretty tough but might crater a little.
Link Posted: 11/30/2016 12:06:10 PM EST
A2 is going to be around 64 Rc or 720 Brinell as quenched, and will most likely shatter.

Shooting for 500-550 would be tough with A2, as it drops off fast after 600

I'd ask him to temper at 1000, then stress relieve at 975. This should give you a hardness of about 575-600.
Link Posted: 11/30/2016 12:22:37 PM EST
Thanks for the quick responses. First piece he said will be 60-62. Second one I told him to draw down to 52-55.

Seems you guys have this down pretty good. Should I not bother with the untreated piece? temper it to mid 50s while the others are in the oven or experiment and see what happens with no treatment?

He just finished the a2 this week . gunna have to a wait till Tuesday to get them in.
Link Posted: 12/17/2016 5:41:57 PM EST
[Last Edit: 12/17/2016 5:44:14 PM EST by sorionc]
Just got back from range. out of heat treat I had one piece at 52-56 one at 60 and one untreated. I didn't take the one hardened to 60 today. 

these were shot @300yds. Out of AA Grendel with 20" shilen barrel. Using factory amax's

untreated plate dimpled slightly. Roughly 1/16"-1/8" 


The piece I had hopes for (52-56) cracked between the holes used to hang the target. And blew a chunk out the back. 





 
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