Smokeless Done some testing today NEED ADVICE

[backstraps]

I tested H4198 today with my 20" Encore 200gr SST / Blue Harvester

I am very happy out to 200 yards.

I want to try and close the gap between 200-300 though.


Here is what I had today:



100 / +2" Group was very nice and tight

200 / - 2.5" Group went out to almost 3"

300 / -12.5" Group had an elevation gap of 1" and spread of 6.5"



From 0-200 I think this H4198 with the SST is getting there fast, and falling on its face beyond the 200 yard stick.

TO be honest I don't understand how the duplex loads work well enough to know what recipe I should try to close my gap between 200-300 yards. I have read that 10/48 4759/4198 performs really well in the short 20" Encore barrels

Could someone tell me the concept of how the duplex loads work?
I have read 10/48 and also read 12/48...other than increased velocities, what trajectory range difference should come from 10/48 and 12/48??

THANKS!

 

[mike243]

a heavier bullet will tighten your groups up is what I read from the ballistics ,I have some 240g but thought about some 200g in 50 cal but the #s drop quick after 200y, still they are fun to shoot due to low kick .If I get some where much over 200y I would want a 300-350g load in a 50 cal.

 

[mike243]

a heavier bullet will tighten your groups up is what I read from the ballistics ,I have some 240g but thought about some 200g in 50 cal but the #s drop quick after 200y, still they are fun to shoot due to low kick .If I get some where much over 200y I would want a 300-350g load in a 50 cal.

 

[Roost 1]

How h4198 are you using? 200gr bullet dropping 12" at 300yds not to
Bad for a mzl....not saying you can't do better.

 

[Roost 1]

Not sure a duplex will up your velocity much.. Most people use duplex to reduce temp sensitivey, as to get consistent ignition in colder temps.. Duplex also helps reduce pressure spikes in some situations..

 

[260rem]

did someone check this load 2700 fps seems real fast for a 20" 200gr.

 

[backstraps]

Thanks guys. I was shooting 56.5 gr 4198, .400" 200gr SST

Groups not being as tight as I like, I think the majority of that was simply the shooter. I just didnt think the amount of drop between 200 and 300 sounded right.

When I plugged in some info into JBS, their trajectory charts showed about -9" at 300 @55 degree air temp

I dont think I was close to 2700fps When I was testing loads 57gr 4198 with a 200gr xtp was giving me a 2210 avg

I was impressed at the difference of POI at 300 yards SST vs XTP
The SST was about 3 inchers higher than the XTP.

Without going sabotless, do yall know of a bullet I can shoot with a higher B/C thsn the SST @.265?

 

[Roost 1]

I would bump up to 60 grs and try it.. 62 max.
We use 60gr h4198 in our apex conversions and 195gr Barnes with very good results.

 

[backstraps]

Roost, does the trajectory drop between 2-300 sound about right to you? Have you range tested y'alls out to 300?

 

[Roost 1]

200yds furthest I have shot and I use a burris scope with ballistic plex recticle which works very well out to 200yd.. No reason to believe I would have trouble at 300.. My load with the 195 gr bullet is very close to
30/06 with 180gr best I tell so far. I would expect 7-9" drop at 300. Mine is sighted in 1" high at 100yds. However I did not believe the Barnes has a very good BC and have been told they do not perform great past 300yds. However I have a bud that has killed deer at 400+yds with the same bullet.

 

[backstraps]

Thanks Roost

 

[backstraps]

CR500AFX, are you shooting a 50 cal or the 45

 

[fullstream]

I would bump up to 60 grs and try it.. 62 max.
We use 60gr h4198 in our apex conversions and 195gr Barnes with very good results.

I agree here. A buddy shoots 60 gns out of a 24" at 2600-2650 fps. He has had great results with the 200 sst.

 

[hillbill]

56 grns from a 20" tube should be in the 24-2500 range.

duplex can do two things
1. help with temp sensitivity
2. up your speeds

depending on your barrel profile I would be careful to push it much harder, sounds like a factory TC barrel which is fairly lightweight

from a short tube you could benefit from a booster, creating faster burn sooner in the barrel( quicker pressure rise) with the faster powder (booster) on top of the plug followed by the main charge.

remember the 195s and ssts can be very accurate but also get tossed around by the wind in a big way at long distances (low BC)

I have killed many deer with the little sst with my longest being 356 but like I said the wind will bite you if you have any..

 

[Deer Assassin]

40 cal ml bullets have low bc

you have to remember you are not shooting a rifle






i have killed at 292 with the 200 sst
63.4 h 4198 im getting about 2600 fps 21-22 inc bbl

wife killed 224 with the 195 barns in the ml with close to the same load but slower ml vel

 

[backstraps]

Thanks

I will shoot a few strings thru chrony this weeks and increase to 60gr straight 4198

Will try duplex load and stay with sabots and report back.

What's the formula to calculate pressure?

 

[Deer Assassin]

you can look at a shot sabot and tell if the pressure is to much

 

[backstraps]

Okay good.

I've been keeping a close eye on them.

Excessive pressure....will it put a hole in the bottom?

 

[Roost 1]

Stuck or bulged primers is also an indication of too much pressure... Sabot petals should be opened no more than 90 degrees...

 

[backstraps]

Encore with Jim Hendershot "SHOTS" trigger, Katahdin 20" 45-70 barrel, Slufoot conversion with PR plug, Winchester 209, Hornady 200GR 100yds


I think the conversion did pretty well. I plan to stretch it back out to 300 this week (weather permitting) to see what my drop off will be.

I didn't expand too wide on the charge testing but did make a couple jumps. Went from 58 to 58.5, 59.0 Then tested increments 59.5, 59.8 and 60

Once I settled on a charge that I felt was testing the best, 60GR H4198
I shot a 10 shot group. Only had one sabot that was questionable, but sent pics and it was fine after all. The primers were in great shape.

 

[backstraps]

10 shot group could've been tighter, again the shooters fault, not the gun. Coming off prone/bipod

 

[Roost 1]

Good shooting... I believe you are on to something.
If you do not visit Doug's message board, you need to.
The best place for SML...

 

[backstraps]

Good shooting... I believe you are on to something.
If you do not visit Doug's message board, you need to.
The best place for SML...

Thanks Rooost1.

DA sent me there when I was getting this project started. I have done a ton of lurking on Dougs.

DA also gave me the advice to go with this setup since I already had an Encore. Sent me to the site, and the guy to do the conversion.

I also spoke with HillBill on the phone prior to going with the Encore route. Would still love to own one of his builds!!!!

Great group of guys on this site! Appreciate everyone's help.

 

[Rubberduck270]

Sabots look good for this type of weather. You'll be more than fine come fall/winter. As was previously stated, a duplex might bring your velocity up a little but it'll also show on the sabot pressure. The way she's shooting right now I'd forget the duplexing and start sharpening my knife ;)

 

[Andy S.]

Sabots look good for this type of weather. You'll be more than fine come fall/winter. As was previously stated, a duplex might bring your velocity up a little but it'll also show on the sabot pressure. The way she's shooting right now I'd forget the duplexing and start sharpening my knife ;)

x2

 

[backstraps]

Thanks guys.

 

[hillbill]

excessive pressure signs;

1. erratic groups/ keyholing
2. torn edges on sabot skirt
3. drilling (hole in base)

ripped off petals don't mean excessive pressure, pay attention to the base

 

[backstraps]

excessive pressure signs;

1. erratic groups/ keyholing
2. torn edges on sabot skirt
3. drilling (hole in base)

ripped off petals don't mean excessive pressure, pay attention to the base

Thanks!! I appreciate the heads up.