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Post by corbin1988 on May 5, 2023 18:20:14 GMT -8
I'm a new user on this forum, so bear with me while I figure out how everything works. Anyhow, I have recently gotten into messing around with some oddball AR builds. A buddy of mine has a gun shop and somebody brought in a 23" bull barrel with a rifle length gas port. It's a BHW barrel marked as 20LBC. I am assuming that the 20LBC is a grendel necked down to .20 cal. I bought the barrel at the very agreeable price of $100, which makes this a budget wildcat build. However, I dont want to mess with it if it's not a decent round or if I can't slam out the shells for it. If anyone could provide me with any input, information, load data, etc. I would be grateful. I am literally at 0 on this. I have no idea where to even start making the brass. I have no idea what powder/primers/bullets this thing will like. Anything helps. Thanks.
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Post by GLSHOOTER on May 5, 2023 18:22:48 GMT -8
I'll write a big note tomorrow.
Greg
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Post by GLSHOOTER on May 8, 2023 9:34:03 GMT -8
I'm a new user on this forum, so bear with me while I figure out how everything works. Anyhow, I have recently gotten into messing around with some oddball AR builds. A buddy of mine has a gun shop and somebody brought in a 23" bull barrel with a rifle length gas port. It's a BHW barrel marked as 20LBC. I am assuming that the 20LBC is a Grendel necked down to .20 cal. I bought the barrel at the very agreeable price of $100, which makes this a budget wildcat build. However, I dont want to mess with it if it's not a decent round or if I can't slam out the shells for it. If anyone could provide me with any input, information, load data, etc. I would be grateful. I am literally at 0 on this. I have no idea where to even start making the brass. I have no idea what powder/primers/bullets this thing will like. Anything helps. Thanks. Sorry for the delay but sometimes life gets in the way of fun. The 20 LKBDC is a necked sown 6.5 Grendel as you have surmised. It maintains the same shoulder height and angle of the parent case. The only slow down on the cartridge is the initial process of making the cases. I use a Redding Type S Full Length Bushing die in 6.5 Grendel and the appropriate shell holder. The process for brass making is to size the case down in steps. It cannot be done as a one pass endeavor. I prefer to take it down from my initial size of approximately with a 280 bushing then a 270 and then a 260 bushing or what ever would give me 0.003 neck tension based on case neck thickness. bushing. You must first chamfer the outside of the case to make sure it does not hang up on the square edges of the die. Of course any brand of bushing die could be used but you want a FL version. Imperial Sizing wax is used during the case forming but after that I just use my uual lube like One Shot. It is not necessary to turn the necks although to make the very best cases it would behoove you to do that to clean them up as the necking down process will often cause unequal thickening on one side or the other. I never use an expander ball on my cases when loading them. To do so negates the whole concept of the neck bushing system. If I use Lapua case the flash holes are smaller and I swap in a 20 or 6 PPC decapping rod to fit the hole. If I use other brands with a furl size hole I still use it although you could just swap in a standard decapper pin. On those I want to do off press I use a regular Wilson whack a pin set decapping rod for standard or PPC hole size using my brass hammer and pedestal. I use a Sinclair distance to lands tool to adjust bullet seating depth using a fired case and the Hornady Headspace tool to set my shoulder bumps. Losing is normal like any other bottle nexk case. I am using CCI 40 or Rem 7 1/2 primers. I have 20 and 24" tubes. Speeds are good with good case life with Lapua. I've shot 32's up to 55's. The 1:10 stabilized the 10's BTW. In the 24" I've pushed 32's to 4276 with H4895 TAC gave me 4201 On 35's H4895 did 4146 40's with H4895 at 4111 with TAC doing 4005. I shot some 55's in teh 20 and got 3343 with H4896 and 3332 with 8208. I use ASC Grendel magazines. The case is a hoot to shoot and unique for sure. Do the initial 100 forming takes about an hour or so then after that it is the same speed as anything else. Let me know if you have any questions. Greg |
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Post by corbin1988 on May 8, 2023 13:46:48 GMT -8
Thanks for the reply and all the helpful information Greg. I really appreciate it. So I finally had time to sit down and explore the forum; I found the posts from years back regarding the 20LBC. It looks like you have put in the time and work into the science behind the 20LBC wildcat. It definitely sounds like an interesting round. I have a few projects in the works right now but based on your testimony, it seems like making the brass and loading the shells is within my realm of capacity, so I do intend on starting the build very soon. I will update the thread as my build progresses. Thank you.
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