H110 and berrys 220s Bolt lock back 80 percent

Moderators: gds, bakerjw, renegade, bamachem

Post Reply
Slowbolt
New Member
Posts: 7
Joined: Sat Mar 26, 2022 8:43 pm

H110 and berrys 220s Bolt lock back 80 percent

Post by Slowbolt »

Currently working up some plinking sub loads with H110 and berry’s 220s Platform is a sig rattler 5.5 length barrel. Last load tested was 15 rounds at 10 grns. No can. Still in jail after 13 months. Cycling just fine except on last round. It locks the bolt back 80 percent of the time. Tested 10 rounds for bolt lock.

Average fps was 987 Fastest was 1027 and slowest was 934 Bolt locked back on the slowest but not on the fastest. Not sure that’s relevant but thought I would throw it in. My question is should I bump it up around a 1/2 grn or just switch powders entirely. The highest grn weight I found published was 10 grns for these. I’m not seeing pressure signs but still a little nervous as I’m still learning hand loading. I would love for this powder to do the trick but don’t want to take unnecessary risks either. I understand there some risks in reloading, and I expect it. Just thought I would ask the internets advice first.

I have a bunch of 1680, cfe blk and lil gun on hand as well. Loading on a Dillon 750 so the charges are all thrown. Not interested in tiny groups yet. Just looking to make some descant batches of ammo. Oh brass tested was converted lake city brass.

Thanks guys!
User avatar
dellet
Silent But Deadly
Posts: 6967
Joined: Fri Nov 30, 2012 1:25 pm

Re: H110 and berrys 220s Bolt lock back 80 percent

Post by dellet »

Without seeing the data you are using, the 10 grain maximum is a garbage number, that leads to a lot of confusion.

Maximum charge weight should be based on pressure, not velocity. 10 grains and likely 1050fps, is used to have a subsonic load in a 16” barrel. If you look at Sierra, Hornady data you will find max loads by pressure and around 12 grains, 1200 fps.

You have wiggle room to add some powder for velocity, that may or may not cure the problem. The first thing to do is weigh about 20 charges, they need to be within .2 grains max.

Since only the slowest round locked the bolt back, unless you can confirm powder charge, I would move the bullet out .010-.015” and see if you get more consistent lock on empty. What you are doing is manipulating the burn rate of the powder. The slower velocity, indicates less complete burning, causing a higher pressure at the muzzle where it is needed to cycle the action. It’s a bit counter intuitive.

It will be a balancing act of moving the bullet out, adding powder, moving the bullet out. To get the velocity you want, and have full operation.

The flip side is that once you have the suppressor, the extra back pressure will likely cure the problem, and you won’t need to go through all that.
300 Blackout, not just for sub-sonics.
Slowbolt
New Member
Posts: 7
Joined: Sat Mar 26, 2022 8:43 pm

Re: H110 and berrys 220s Bolt lock back 80 percent

Post by Slowbolt »

Thank you! Btw 2.25 was oal
Slowbolt
New Member
Posts: 7
Joined: Sat Mar 26, 2022 8:43 pm

Re: H110 and berrys 220s Bolt lock back 80 percent

Post by Slowbolt »

Btw when you say moving the bullet out what your say make the oal longer right. These cartridges are already at magazine length. So may have to just give up on this powder for subs in this gun. I ran another test today at 10.3 grains with the same lock back results. About 80 percent. Average was fps was 1025 I did test with the same mag and with some factory grn 150s. 100 percent lock back. I’m going to do one more test and bump it up to 10.5 grns. I think that will put me right in that 1050 fps range. We shall see if locks the bolt back. If not I think I’ll try some 1680
Post Reply

Who is online

Users browsing this forum: No registered users and 127 guests