Subsonic HELP

[tmshot]

I thought about posting this in the ammo/reloading section, but I know I would get more help here. First let me say that I know it would be probably better to have a .22 and a suppressor for it for the ultimate quiet. However, I currently have neither....YET! So I am trying to get a good .223 subsonic load together. I have been researching and have found alot of guys say to use the heaviest bullet your gun can handle to have the hardest punch. So my gun really likes the sierra 69r hpbt. I loaded up a few loads with them and nothing but keyholing at 100yd. Also I don't think any of them were truly subsonic.

First load.
69gr hpbt
5gr trailboss

Second load
69gr hpbt
4.5 gr trailboss

Since both loads were not subsonic and still keyholed I gave up from there.
Do I need to go with a lighter bullet?
Should I be shooting shorter (like 50 yds) to look for tumbling?
Any advice/loads to share?

The gun is a remington 700 sps tactical, 20" 1:9 twist barrel.

[ungawa]

I downloaded this calulator, there are others:

http://members.shaw.ca/cronhelm/file...Calculator.zip

I found second hand info on the web that the length of that bullet is 0.900 inches. Since you reload, I'm sure you know the actual length.

Using that information it looks like the bullet is not stable below 1700 fps out of a 1/9 barrel but is fully stable out of a 1/7 barrel at 1000 fps and possibly lower.

I would suggest you try something like that to figure out what you need to do. You you have a projectile stability calculator? I can't vouch for the one I just used.

[tmshot]

Hey thats pretty handy.
No I did not have a bullet stability calculator. I will look around online and compare results of this calculator with others I find. Looks like 55 gr will work.
Thanks

[knight0334]

1:9" is suitable for 69gr bullets near 2700-3000fps, but if you're pushing them under 1100fps you will need a hellava lot faster twist rate. Something around 1:6" or so..(guessing)

Remember, the longer the bullet or the lower the velocity - the faster twist rate you will need. Combine longer bullets with slower velocities and you compound the issue.

[knight0334]

1:9" is suitable for 69gr bullets near 2700-3000fps, but if you're pushing them under 1100fps you will need a hellava lot faster twist rate. Something around 1:6" or so..(guessing)

Remember, the longer the bullet or the lower the velocity - the faster twist rate you will need. Combine longer bullets with slower velocities and you compound the issue.

Damn I'm good..

http://kwk.us/twist.html

Plug in:

.90" for bullet length for 69gr bullet
.224" for diameter
1100fps for velocity
leave SG at 10.9 for lead bullet with copper jacket
and you get 1:6.5" for required twist rate..

[Toxicodendron11]

I started a thread in the ammo/reload section on this subject.



http://forum.pafoa.org/ammunition-re...223-loads.html

[tmshot]

Toxic,
Did you get anywhere with your loads? I just got some 55 gr spitzers.
4 gr trailboss was still NOT subsonic. I don't have a meter to see how fast they were, but they were cracking.

[Toxicodendron11]

Sub sonic, not quite. But they were much quiter than standard load. Next I am going to try Bullseye. Seating the bullet backwards has significantly reduced the keyholing.

[knight0334]

Sub sonic, not quite. But they were much quiter than standard load. Next I am going to try Bullseye. Seating the bullet backwards has significantly reduced the keyholing.

Thats because the heaviest part of the bullet is now forward. The bullet is no-longer fighting its natural tendency to shift its heaviest portion to the lead of it's flight path.

[39lasalle]

Not sure if this really matters here but my Brother-in-law has reloaded sub-sonic .308 fro me and I am using a round nose bullet 150gr.

I do not reload and not sure if they make a round nose .22 cal bullet but if they do, I would start there.

39