sierra 220gr rn subsonic 308 load

[timelinex]

I'm preparing to receive my can soon and I want to start ordering components to make a subsonic round.

I already have winchester brass and 215M primers (I read magnums would be better to use than my cci br2's I regularly use for 308.) I am planning on buying some trailboss shortly.

The last piece of the puzzle is what bullet to get. I know many recommend the hornady 180gr RN, but it seems like its mostly favored because how stable it is for people with 1:12 twists.

My rifle is a 1:10 twist 24" barrel. So I think I want to go on the heavier side. I know Lapua makes 200gr subsonic bullets, but they are really on the expensive side. I know most any other match and boat tail bullets generally have bad accuracy, so those are ruled out.

Has anyone had any experience with Sierra's pro-hunter 220 gr round nose bullets? They are currently in stock and Seem like they might be the heavest and best bet that I can stabilize. However I can't find any threads or talk about them used subsonically.

 

[pprochnow]

Are you looking to hunt big game or plink, varmints, etc?
I shoot the 150 gr round nose made for the 30-30 rounds. (Super cheap) I don't hunt big game with ss, but it does the trick on everything else. Trail boss is a great powder. I am around 9.7 grains if I recall correctly. 1050 fps. In all reality hunting with full power is by far the best. I filled a two doe tags this winter with full power loads, dropped them both in the same spot. they had no idea where the bullets were coming from. It's pretty enlightening to hear where the bullets are in flight and hear them hit the animal.

 

[ZombieMonkey]

No experience with those. Been shooting 200gr matchkings over 10.5 gr of trailboss with standard primers. Works amazing and very consistent results. Was not my first choice in bullets, but I had a couple hundred and they've been great. I don't personally bother with the magnum primers or opening the flash holes up like some do, I have not seen any reason to do so with my testing.

 

[SPAK]

I've used the Sierra 220 round nose, results were ok... The best bullet I've used so far in regards to accuracy, is the 208amax over trailboss.

 

[sic65stang]

Those 180's over trailboss will likely give u good accuracy and repeatability. I have only had the chance to get mine out to 300, but it is reliable on a 12" plate (never been on paper yet). In theory a 220 would stablilize, but drop like a rock. For example my 308 from zero at 100 is exactly 5MIL (yes MIL not MIN) low with subsonic, 200, another 5.5 MIL, and at 300, another 5.5 MIL. I dont even want to think about the drop on a 220. Just food for thought.

 

[timelinex]

Maybe I should of clarified my use for these. These will not be for hunting. This will be strictly for amusement at this point. So I'm not worried about energy or terminal ballistics.

So you guys are saying the 220s will be overboard? I was under the impression that the heaviest I could stabilize the better. Since velocity is maxed out at 1050, what's the advantages of a lighter bullet?

How are the 208 AMAX so great when they are a boat tail.

 

[sic65stang]

I didnt have any luck with boat tails. The advantage with the lighter bullet is less drop. You are limited by velocity, and gravity is a constant. The lighter the bullet the less it will be effected by gravity. I know the thought that typically with supersonic velocities you want the heaviest bullet to buck wind etc, but with subsonic you are mainly battling gravity IMO.

 

[Absolution]

I didnt have any luck with boat tails. The advantage with the lighter bullet is less drop. You are limited by velocity, and gravity is a constant. The lighter the bullet the less it will be effected by gravity. I know the thought that typically with supersonic velocities you want the heaviest bullet to buck wind etc, but with subsonic you are mainly battling gravity IMO.

Umm isn't gravity is a constant? No matter the weight all objects fall at the same speed. The only thing that makes it look like a bullet falls faster is the velocity. ( How much distance is covered in time)

 

[Sonic Crack]

I didnt have any luck with boat tails. The advantage with the lighter bullet is less drop. You are limited by velocity, and gravity is a constant. The lighter the bullet the less it will be effected by gravity. I know the thought that typically with supersonic velocities you want the heaviest bullet to buck wind etc, but with subsonic you are mainly battling gravity IMO.

Sorry but your way off base. Run the numbers in shooter program, the drops between a 180 round nose and a 220 SMK are almost identical (within .1-.2 mil) out to 4-500ish yards. Then the SMK takes over because its heavier and retains more velosity and energy. Totaly opposite of what your saying

 

[biffj]

The whole point behind subsonic shooting is to retain as much energy as possible while reducing noise. Because of that the advantage in the subsonics is normally with the heaviest bullet you can throw. On the other hand the heaviest bullet may not stabilize and I think with a 10 in twist you're on the edge with a 220 gr bullet with a pointy end and a boattail. I've done some repairs on suppressors used with that bullet and twist in common. Mostly endcap or baffle strikes. Sticking with the lighter bullets for you would make sense from that standpoint. We are shooting 30-221, 300 whisper, 300 blackout using twist rates of 7-8 inchs in order to stabilize these long heavies so 10in isn't really there. On the other hand if you want to toss the round nose 220 you would likely be fine. The round nose bullets are normally much shorter and need less spin to remain stable. The only problem with them is that they have more drag and slow down quicker so they don't have the range the slicker HPBT's do. If you're only shooting out to 300 it may not make much difference....

Frank

 

[ksthomas]

Drop IS a constant; 32.17 fps/ps. Regardless of bullet weight or velocity, they all drop at 32.17 fps/ps. When dealing with a set velocity limitation, such as we are with subsonic rounds, the only thing that changes with weight, is energy.

 

[Absolution]

Drop IS a constant; 32.17 fps/ps. Regardless of bullet weight or velocity, they all drop at 32.17 fps/ps. When dealing with a set velocity limitation, such as we are with subsonic rounds, the only thing that changes with weight, is energy.

+1!! I was too lazy to look it up lol.

 

[sic65stang]

I guess I was misunderstood. Like I said, drop is a constant. I was wrong in thinking that the 180 would drop less than the 208 because of its weight. I suppose there isnt much time for gravity to effect the bullet. I guess I learned something...

Still I didnt have any luck with 168/175/178 boat tail bullets so I will be interested to see if the 208's work.

 

[Ol Rob]

It is funny how the question gets so turned around. The original poster is looking for info on the 220gr ROUND NOSE. I am following this thread with interest because I have the same question. Because the ballistic coefficient is so low on these bullets I would expect them to slow down faster than the SMK's and Amax's, resulting in more drop at the same distance. More time of flight equals more drop. But at sub sonic speeds, just how much does the BC even come into play? These questions can only be answered by someone who has tried both.
anyone? anyone?
Please post if you have tried these. Rob

 

[rjacobs]

Buy a box and try em. Shoot em at 25, 50, 75 and 100 and watch for signs of key holing. If none, go for it with the can.

220g SMK's are barely stable in a 10 twist 20" barrel at subsonic speeds
208g AMAX are NOT stable in a 10 twist 20" barrel at subsonic speeds

Somebody on here must have the program for determining stability factors out of certain barrels that can plug in the 220g RN specs and see what the stability factor is.

 

[timelinex]

Buy a box and try em. Shoot em at 25, 50, 75 and 100 and watch for signs of key holing. If none, go for it with the can.

220g SMK's are barely stable in a 10 twist 20" barrel at subsonic speeds
208g AMAX are NOT stable in a 10 twist 20" barrel at subsonic speeds

Somebody on here must have the program for determining stability factors out of certain barrels that can plug in the 220g RN specs and see what the stability factor is.

Obviously I can try it out myself, however I usually post on here before wasting time/money bc most likely someone has tried it already.

I'm not so much worried about stability, as much as overall performance and accuracy.

 

[pprochnow]

Maybe I should of clarified my use for these. These will not be for hunting. This will be strictly for amusement at this point. So I'm not worried about energy or terminal ballistics.

So you guys are saying the 220s will be overboard? I was under the impression that the heaviest I could stabilize the better. Since velocity is maxed out at 1050, what's the advantages of a lighter bullet?

How are the 208 AMAX so great when they are a boat tail.

If you are not worried about energy or performance, I would pick a cheap and available size between 150 and 180 grain bullet. Check for key holes in paper both close and further out. A 150gr round nose subsonic shot at p.b.r went through two stacked 2x4s and a concrete block. Still plenty of energy for varmints.

 

[timelinex]

If you are not worried about energy or performance, I would pick a cheap and available size between 150 and 180 grain bullet. Check for key holes in paper both close and further out. A 150gr round nose subsonic shot at p.b.r went through two stacked 2x4s and a concrete block. Still plenty of energy for varmints.

Well while I'm not worried about energy, I am worried about drop/wind performance. I don't need energy since I'm not hunting, but I want to be able to hit the target I'm aiming at as easily as possible...

 

[timelinex]

Ok, just bought some trailboss and 220gr sierra round nose bullets! their length seem to be about 1.3", so even at a very slow speed in very cold weather, according to the formula, my 308 should not have any problem stabilizing these.

What range of trailboss do I test these with? Its hard to find any data on this combination for subsonic speeds. I'm thinking start at 11gr and go down to 10gr in .2gr increments?

Lastly, what seating depth should I do? I usually jam my bullets into the lands, but as I understand thats a no-no for subsonic. Do I just give it a .002" jump that people usually give their bullets?

 

[biffj]

It took me a bit to see that you were asking for 220RN info but I did finally see it.....
I have fired 200gr round nose in the 30-221 thinking they would be better for putting holes in game that would kill them quicker than the spitzer types. What I found is that it doesn't seem to make much difference in subsonics what shape the nose is for killing things. It does make a big difference in ballistics. The draggier round nose will drop more and at the ranges we were shooting (up to 400yds) the drop is substantially higher with the round nose. I don't know about wind as we weren't shooting when it was windy. The drop at 200 was about 10-12 inches more with the RN compared to the SMK of the same weight. It also took about .5 to .7gr more powder to get the same velocity and we figured that was due to the extra contact area on the bullet. I'm sure they'll work ok and accuracy seemed to be ok though not as good as the SMK's but minute of pig is all you normally need....Performance on target was about the same as the SMK, 100yds you peeled the jacket off the bullet and splattered lead on steel, 200yds you squished the whole bullet flat, 300yds it flattened the front half and 400yds about the first third. Didn't seem to matter that the round nose was lead tip.

Hope that is more applicable info to the question.

Frank

 

[timelinex]

Ok guys, I was able to go to the range and something is deffintely terribly off.

After some research, it seems like with 200-220gn round nose bullets people setting on the mid 10 grain range of trailboss.

So I loaded up between 9.9 and 11gr. Here is my load info:
220gr sierra RN
winchester brass
COAL: 2.810
Federal 215m primers

I fired 2 rounds of the 11gr before I quit. One shot at 430 FPS and the other 380 FPS. I was shooting at the 100 yard line and they actually hit ground at 50 yards or so. There was also what looked like powder down the barrel.

So am I just seriously undercharging? The case actually looks filled up pretty well.

Anyone have any idea what is going on?! The only thing I could think of is its 2x fired winchester brass. If you compare it to LC brass, it has atleast 2 more grains of space.

 

[SPAK]

In my 30-06 case I think I'm using around 14 gr of trail boss with a 208 amax running right around 1090fps... I'll have to re confirm he charge when I get back into town...are th bullets stabilizing?? Chrono error??

 

[rjacobs]

I use 10.5g of Trailboss with a 180g RN to give you an idea. 11g with a 220g bullet would be way to little IMO.

I would think something in the 12-13+ grain range would be needed.

Trailboss works opposite of what we normally think for reloading in that when you put a bigger bullet in you also up the powder charge. Generally a bigger bullet requires LESS powder, but not with trailboss and the subsonics.

 

[leadbullet]

good luck finding your components of choice, right now is more of a buy whatever you can find.
cheers.

 

[timelinex]

good luck finding your components of choice, right now is more of a buy whatever you can find.
cheers.

...? I already have everything u need. I'm not sure if u followed the thread to the end, but now I'm just having load development issues/surprises

 

[UrbanSi]

If you are worried about crunch from trailboss you can always try red dot.

Your FPS seems really low, I would keep working up a load with the trailboss until you run out of room in the case.

It does suck that you have to "waste" bullets but it's all part of load development

 

[timelinex]

If you are worried about crunch from trailboss you can always try red dot.

Your FPS seems really low, I would keep working up a load with the trailboss until you run out of room in the case.

It does suck that you have to "waste" bullets but it's all part of load development

Yea I hear you, just the name of the game I suppose.

How would I know when I know when it's too overfilled? I've never loaded a compressed load. It doesn't seem like I would feel the compression through all the steel of the rock chucker press.

Yea the fps was super low. It sounded like someone just spit a really big wad of paper through a straw haha

 

[lead ƒarmer]

Keep us updated with your progress. I actually just bought those same bullets for subsonic shooting in my .308 win. I would love to help you, but I don't have my suppressor just yet, should only be a week or two more. I would love to see your results and what you learned along the way. I will definitely let you know what works for me if I get my can faster than expected. My supplies:

Savage 10FP 308 w/ 24" barrel
Sierra 220gr Round Nose
Trailboss
FC Brass
Federal primers, either large or magnum

 

[UrbanSi]

Yea I hear you, just the name of the game I suppose.

How would I know when I know when it's too overfilled? I've never loaded a compressed load. It doesn't seem like I would feel the compression through all the steel of the rock chucker press.

Yea the fps was super low. It sounded like someone just spit a really big wad of paper through a straw haha

I would attempt to test case capacity first. Fill up a case and level off the top.
Weigh what you have, maybe do this with different headstamps to get an idea what accepts the most powder.

As for the crunch, its called that for a reason. You will hear it usually when you are compressing a load. Another way to see/test a compressed load is to take a slightly over belled case and seat a bullet. With less tension it should back the bullet out some to give you an idea on how/if you are compressing a load.

You could also try vibrating or tapping a case after the powder drop, see if it starts to settle some before seating the bullet. This works with a lot of stick powders like IMR-4895 and even tiny ball like W748.

Or with a different bullet, maybe a 200gr or Hornady 195. The the extra case capacity should give you an idea on what happens when you have more room to work with.

Don't be afraid to play with the OAL some more, 2.810" with a little more room could increase case capacity. Just because some others don't have luck with COL doesn't mean you can't look for a little more room depending on how long the throat is on your rifle.

And finally, things are going to change when you add the can. You'll still need some minor tweaks once you screw the extra metal on.


Timelinex, if you want to try some Hornady 195 BTHP's I'll ship you out 10-15 to try out. LMK
I am single loading these .020" off the lands (@2.890") with some success, this is of course on a Remington.

 

[timelinex]

I would attempt to test case capacity first. Fill up a case and level off the top.
Weigh what you have, maybe do this with different headstamps to get an idea what accepts the most powder.

As for the crunch, its called that for a reason. You will hear it usually when you are compressing a load. Another way to see/test a compressed load is to take a slightly over belled case and seat a bullet. With less tension it should back the bullet out some to give you an idea on how/if you are compressing a load.

You could also try vibrating or tapping a case after the powder drop, see if it starts to settle some before seating the bullet. This works with a lot of stick powders like IMR-4895 and even tiny ball like W748.

Or with a different bullet, maybe a 200gr or Hornady 195. The the extra case capacity should give you an idea on what happens when you have more room to work with.

Don't be afraid to play with the OAL some more, 2.810" with a little more room could increase case capacity. Just because some others don't have luck with COL doesn't mean you can't look for a little more room depending on how long the throat is on your rifle.

And finally, things are going to change when you add the can. You'll still need some minor tweaks once you screw the extra metal on.


Timelinex, if you want to try some Hornady 195 BTHP's I'll ship you out 10-15 to try out. LMK
I am single loading these .020" off the lands (@2.890") with some success, this is of course on a Remington.

Ok so my winchester brass can fit around 18.5gr of trailboss total. Then I did some experimenting with a piece that had a loose neck where I can hand seat the bullet. I can fit around 14-14.5gr of trailboss in the case before the bullet bottoms out at a longer distance than I seat. So what do I do with this information?

Thank you for the generous offer UrbanSi. I will first try to do everything I can to make my combination work, and if it doesn't, then I might take you up on your offer!

 

[ZombieMonkey]

Was it a typo when you said you were seating .002 off the lands? As stated by UrbanSi a 0.020 off the lands is more appropriate for the subsonic loads. Did you verify the chronograph was working properly with other loads just to rule out a chronograph error? I'd expect your load with that bullet to be 10.5-11.0 with that specific bullet to the the number needed for the desired velocity.

 

[Will Fennell]

I've had great success with the 190 gr Nosler BTHP( relatively inexpensive bulk price) over 10.5 grs of Trailboss. Runs 1040 fps out of my 16.5" 308. Very accurate.

 

[rjacobs]

I'd expect your load with that bullet to be 10.5-11.0 with that specific bullet to the the number needed for the desired velocity.

10.5g would be low for a 220g IMO. I load 10.5g for the 180g. I would expect his load to be in the 12g range personally, but I have no experience with the 220g RN, just 180g RN and Spitzer's. I do know that with trailboss and subsonics its a different relationship when you go up in bullet size from what we traditionally think in the supersonic world. You increase powder charge as bullet weight goes up. In the supersonic world you traditionally reduce powder charge as bullet weight goes up.

timelinex: since you know that ~14g produces a compressed charge at a longer than desired OAL, I would back off even more until you are barely touching your powder(you will know it on the press handle) when seated to your desired OAL. As long as you have a bullet puller all this takes is a little time and no wasted components. Thats where I would start with the charge and work down in .1 or .2g increments until you get the speed you want and always checking for bore obstructions.

Im guessing you are going to end up in the mid 12g range.

 

[SPAK]

Just checked my load data for .30-06 sized case using win brass I ran 13.5gr trailboss under a 208 amax seated .020" off the lands... I suspect you'll probably end up between 12.5-13.5 gr trail boss for the 220gr RN....308 smaller sized case would normally take less powder charge, but the 220gr bullet is heavier Which will take more powder to get the target velocity.... I always start high and work down shooting over a chrono at 50 yards without the can on first to make sure there is no key holing. More important than velocity is making sure your bullets are stable otherwise you may end up with a baffle strike...once I see a decent velocity around 1050-1100 fps nice round holes in the target, I'll test it wth the can on and see how it goes...

 

[timelinex]

Ok guys after alot more research and googling I found 2 separate threads where people used 220gr rn with trailboss. It looks like on had to use 14.5 and the other 13's. So I guess I was way off! Here and here are the threads

Just to confirm, the chrono was not off, it was right on for my supersonic load.

 

[ZombieMonkey]

definitely a lot higher than I would have expected as my 10.5 over a 200gr SMK puts me right around 1040 fps and a number of others use the same or similar on loads such as the 180gr. Trail Boss is some screwy stuff, hopefully that's the ticket.

 

[phillipjr]

tag for later.

 

[Huckleberry75]

I run the Sierra 220 RN in front of 12.5gnd of trail boss in LC brass and with f210's. gives 1036 out of a 20" AAC. Seated to the canelure. 1moa at 100

 

[Oneshotkill]

Tag. Some good info here

 

[rjacobs]

Wanted to post up since I shot some 220g SMK's today over 12.5g of trail boss loaded to 2.850 through my Rem 700 AAC-SD(10 twist barrel). I dont know the speed, but for sure subsonic. All went straight from 25-100 yards, no keyholes. JBM showed like 1.35 stability with 1.3 as min. Dialed up 5.4 mil from my 100 yard 175g FGMM zero. Groups were pretty decent save for my crappy factory gumby stock doings its usual twisty shifty crap(hope my Rock Solid chassis shows up soon). Everybody at the range was like "WTF are you shooting, its quieter than the guy with the 22lr next to you, but that round is GIANT". I let a couple guys shoot a couple and it was smiles all over the place.

While I wont probably stick with this load because 220g SMK's are 42 bucks a box compared to 28 for 180g RN's, its nice to know they will shoot.

 

[1963vette]

I have been using 168 hornady hpbt under 8 gn of clays. crono is right at 980 to 1010. 24 inch 5r with yankee hill titanium can. 250 box is pretty cheap

 

[rjacobs]

I have been using 168 hornady hpbt under 8 gn of clays. crono is right at 980 to 1010. 24 inch 5r with yankee hill titanium can. 250 box is pretty cheap

That is pretty cheap, even cheaper when you buy 500 count boxes.

Any trouble with them turning around in flight(although not sure how you would know)? I have heard of that happening with the BT type bullets when slung subsonic that was why I was originally using 180g flat base which isnt supposed to turn around in flight.

 

[timelinex]

Wanted to post up since I shot some 220g SMK's today over 12.5g of trail boss loaded to 2.850 through my Rem 700 AAC-SD(10 twist barrel). I dont know the speed, but for sure subsonic. All went straight from 25-100 yards, no keyholes. JBM showed like 1.35 stability with 1.3 as min. Dialed up 5.4 mil from my 100 yard 175g FGMM zero. Groups were pretty decent save for my crappy factory gumby stock doings its usual twisty shifty crap(hope my Rock Solid chassis shows up soon). Everybody at the range was like "WTF are you shooting, its quieter than the guy with the 22lr next to you, but that round is GIANT". I let a couple guys shoot a couple and it was smiles all over the place.

While I wont probably stick with this load because 220g SMK's are 42 bucks a box compared to 28 for 180g RN's, its nice to know they will shoot.

42 bucks a box? They are most definitely 25 a box... I think the place you bought them are ripping you off!

I can't wait to try out my load, just received my 338ba. hopefully this weekend.

 

[rjacobs]

42 bucks a box? They are most definitely 25 a box... I think the place you bought them are ripping you off!

220g SMK's NOT 220g RN. Even from Powder Valley which is one of the cheaper suppliers they are $40 a box. The RN yes are 27 per box, but that is not what I was shooting.

 

[timelinex]

220g SMK's NOT 220g RN. Even from Powder Valley which is one of the cheaper suppliers they are $40 a box. The RN yes are 27 per box, but that is not what I was shooting.

Oh ok, sorry about that, misread!

 

[1963vette]

Shot @ 200 all holes are round, not the best groups. 10 shot group at about 4 ". I haven't messed around with different loads yet, but hell at that fps what the hell. This load is on imr website

 

[timelinex]

So I finally got to the range.
14.3 = 1060
14=1030
13.7=900s

So it seems I will need something between 14 and 14.5 grains.

Everything landed nose forward, however accuracy was horrible. I'm talking about 1 ft groups horrible. And velocity was inconsistent... 1 round out of 3 rounds would be about 100fps less.

Now that I know the grain range,
What's next? How can I make it more consistent? Should I mess with seating the bullet into the case further, to make sure powder is evenly distributed?

The last thing that I can think of is that the brass o's neck sized for SMK's, and these bullets must be slight smaller because they are barely hanging in there. The bullet doesn't fall out but if I press on it with moderate force it does fall through. Could this cause bad accuracy?

 

[rjacobs]

I crimp all of my subsonic ammo. I read something somewhere that the crimp was necessary with trail boss to give it that split millisecond longer to fully ignite which kind of makes sense to me. I think its along the same lines as why guys recommend magnum primers and some go as far as opening up the flash hole to get better powder ignition. I do neither for the record. I have had decent accuracy with both the 180g spire points and the 220g SMK's. I will try to find a box of the 220g round nose and try them out and see what I find.

 

[timelinex]

Well I loaded up 30 more to try next week. 13.9 to 14.5 in .1 increments at the 3.745 coal. Then 3 more at 14.3 (which was the ideal about 1050 fps) at the coals 3.705,3.645,3.920

That covers everything from a little shorter, to about as short as I can go before compressing powder, to as long as I can do for mag length.

Oh, and I used a bushing that's .004 smaller, so now it should have a tight grip on the bullet.

 

[Jesselnick]

I also run 208 amax with trailboss in my 1in 10 twist barrel with great results. It stabilizes good. I have not experimented with anything heavier because I was told the 10 twist may have a hard time stabilizing.

Although it is considered a match bullet it is very effective on hogs!