175 smk @ 2800 fps

[Surgikill]

Hey all, new to the forum here. I am reloading for a CZ 550 Varmint in .308 winchester. I am using lake city brass with a cci 200 primer with 43.5 grains of varget with a coal of 2.820 and 175 smk's. Seeing as the barrel is 25.6" and the lc brass has less case capacity the chrono is telling me that these are coming out just around 2800 fps. My brother is into long range shooting as well and he is telling me that the 175 smk should be coming out at 2600 fps. I am not showing excessive signs of pressure at all. Is there any disadvantage to running these so fast? My gun has a 1-12 twist so it should be stabilized fine. The accuracy is pretty good with a 3/4" group at 200, but as the gun heats up the accuracy deteriorates. I think it is brass quality. Any inputs on this load I would love to hear.

 

[308Gunner]

I am loading 44.6 gr of Varget and getting 2760fps out of a 22" Krieger. Speed is never a bad thing as long as load will group.

 

[VKC]

I'm also getting 2750fps from my 22" Bartlein, so your velocity for 25.6" is possible. Shoot it at 800-1000 yds and see if you DOPE checks out with that velocity.

 

[Surgikill]

I'm also getting 2750fps from my 22" Bartlein, so your velocity for 25.6" is possible. Shoot it at 800-1000 yds and see if you DOPE checks out with that velocity.

I can't get over 200 where I live. What would you recommend to try and improve accuracy? I'm going to change coal and buy some Lapua Brass when I feel like punishing my wallet.

Edit: I could probably get her to 2900. I'm not flattening primers at all.

Sent from GS3 Synergy

 

[VKC]

You are getting enough velocity already. CCI are hard primers and you may miss flattened primers and subtle ejector swipe before a blown primer. 2800fps is more than enough to get you to 1000 yds.

For within 200yds, save your money and use the brass you have. Trim brass to consistent length, chamfer and debur.

Look up ladder accuracy testing and try that. SMKs like up be jumped.

Get an accurate powder measure.

Consider borrowing a concentricity gauge.

 

[bjay]

i must say WOW on 2800 i wouldnt even bother trying for more fps..unless you drop bullet weight to 155 0r 168 or or using 30'' barrel..my milspec 24" using lapua brass 175 smk RL15 2645 is enough for me..altho im trying to get her to atleast 2725..308 with that 175 weight bullet i wouldnt thrust 2900 fps..

 

[Surgikill]

You are getting enough velocity already. CCI are hard primers and you may miss flattened primers and subtle ejector swipe before a blown primer. 2800fps is more than enough to get you to 1000 yds.

For within 200yds, save your money and use the brass you have. Trim brass to consistent length, chamfer and debur.

Look up ladder accuracy testing and try that. SMKs like up be jumped.

Get an accurate powder measure.

Consider borrowing a concentricity gauge.

Every load is hand weighed. Flash hole De burred and they're all trimmed and chamfered. I've read about ladder testing but they said it was only good at 500 yards or so. It's glass bed in a laminate stock. I'm going to sort my brass and try that and then load some up and see if accuracy improves. I'm also going to try some @ 2600 just for kicks so I may not have to burn my barrel out. I need a concentricity gauge big time.

Sent from GS3 Synergy

 

[Surgikill]

Each load is hand weighed and the flash holes have been de burred. Next thing I'm going to do is sort brass and then make some loads up. Accuracy seems to deteriorate when she heats up. I'm going to try some @ 2600 and see if she groups so I don't burn my barrel out.

Sent from GS3 Synergy

 

[Surgikill]

All of the flash holes have been de burred and the brass has been chamfered and trimmed. Next thing I'm going to do is sort the brass by weight and double check some of my measurements. She seems to lose accuracy as she heats up. I don't know if I am just perceiving it that way or if it walks as it heats up. I'm going to try some at 2600 as well just to see if I can get good groups without burning my barrel out.

 

[Jumper]

My CZ550 varmint 308 also seems to lose accuracy as it heats up. Not bad but measurable. Eventually I'm going to try bedding it to see if that corrects the problem. That single-set trigger is awesome isn't it?

 

[rduckwor]

I'm running a 5R barrel at 24" and get 2625 at 43.5 Gr Varget, 2675 at 45Gr. How far out did you set your chrono? 10 feet?

 

[dddoo7]

If all you have is 200 yards, why push it so hot. It will burn more powder, burn out your barrel faster, and wear out your brass much faster. I would spend the money for some lapua cases and then I would look for an accuracy node somewhere around 2600 fps. Accuracy will also increase if you get the bullet closer to the lands, but don't even try that at 2800 fps. I load my 26" 1:12 rem 700 with 43.5 varget and am getting 2600 fps. I only trimmed .003 off my brass and only after the third firing. It is very easy on barrel and brass and will still reach out as far as I need to.

Just my .02.


--Daniel

 

[Surgikill]

If all you have is 200 yards, why push it so hot. It will burn more powder, burn out your barrel faster, and wear out your brass much faster. I would spend the money for some lapua cases and then I would look for an accuracy node somewhere around 2600 fps. Accuracy will also increase if you get the bullet closer to the lands, but don't even try that at 2800 fps. I load my 26" 1:12 rem 700 with 43.5 varget and am getting 2600 fps. I only trimmed .003 off my brass and only after the third firing. It is very easy on barrel and brass and will still reach out as far as I need to.

Just my .02.


--Daniel

I totally agree. I just looked at my targets and it seems I was still above 2600 fps with 41 grains of varget. Pics attached

First is 100 yards

Second is 43.5 @ 200

I'll use the 2600 here and keep some 2800 for when I go out west.

Jumper: I glass bed mine with marine tex and stopped at the receiver. The entire barrel is free floated. I'm going to have to get a torque screwdriver and tighten down my action bolts equally and see if it makes a difference. It could also be me. It was able to put 11 shots of 4064 under .5 moa @ 100 with a hot barrel

Sent from GS3 Synergy

 

[VKC]

You can do ladder testing at any distance. The further out the more velocity variations will be evident, but the further out the more shooter variables are introduced too. Try at 100 & 200 yds.

Agree that your velocity is high. 2600-2750fps is a good range for 308win.

 

[bcrich]

I bet your chronograph is lying...... I know mine does!

 

[Surgikill]

If all you have is 200 yards, why push it so hot. It will burn more powder, burn out your barrel faster, and wear out your brass much faster. I would spend the money for some lapua cases and then I would look for an accuracy node somewhere around 2600 fps. Accuracy will also increase if you get the bullet closer to the lands, but don't even try that at 2800 fps. I load my 26" 1:12 rem 700 with 43.5 varget and am getting 2600 fps. I only trimmed .003 off my brass and only after the third firing. It is very easy on barrel and brass and will still reach out as far as I need to.

Just my .02.


--Daniel

I totally agree. I am going to try around 40.5 grains of varget which should be in the ballpark for 2600. I'll keep the fast rounds for when I go out west and just use the slower ones for around here. I'll also sort brass as well and see if that makes any difference.


Jumper: I glass bed my rifle with marine tex and I only bed the action. It does make a huge difference. I also need to get a torque screwdriver so I can get both action bolts locked down to the same spec which should help as well.

 

[scudzuki]

You can do ladder testing at any distance. The further out the more velocity variations will be evident, but the further out the more shooter variables are introduced too. Try at 100 & 200 yds.

Agree that your velocity is high. 2600-2750fps is a good range for 308win.

A ladder is run at 300 yards or more if possible.
An OCW is run at 100.

Joe

 

[bh-ltr]

I just did a chronograph test on my load.

175SMK
Lapua Brass
2.800" COAL
44.5g Varget
Federal 210 Primer
20" Stock LTR barrel
Velocity 2580

Same Load with Remington 9.5 primer
Velocity 2601

Same load (w/ Rem primer) with 44.3g of Varget
Velocity 2577

I ran through this test as I was trying to match my previous velocities and found that I need to remove 0.2g of Varget as I change primers on my load. This new load has followed all my old dope and has been tested to 1147 yards. All velocities measured with a Magnetospeed V2 at the muzzle.

~Brett

 

[VKC]

A ladder is run at 300 yards or more if possible.
An OCW is run at 100.

Joe

Agree with what you stated but he is limited by range.

Could use a chrono and calculate your SD as well.

 

[scudzuki]

Agree with what you stated but he is limited by range.

Could use a chrono and calculate your SD as well.

Yeah, I saw that.
I tried a ladder at 200 once (the 300 was full and I couldn't wait for a table) and got so-so results.
Not really a fan of the ladder, as one round at each charge weight does not yield enough data points IMHO.

I believe the OCW is a more conclusive test and it has yielded better results for me.
The fact that it's run at 100 yards only makes it easier.

Joe

 

[Pinecone]

I just did a chronograph test on my load.

175SMK
Lapua Brass
2.800" COAL
44.5g Varget
Federal 210 Primer
20" Stock LTR barrel
Velocity 2580

Same Load with Remington 9.5 primer
Velocity 2601

Same load (w/ Rem primer) with 44.3g of Varget
Velocity 2577

I ran through this test as I was trying to match my previous velocities and found that I need to remove 0.2g of Varget as I change primers on my load. This new load has followed all my old dope and has been tested to 1147 yards. All velocities measured with a Magnetospeed V2 at the muzzle.

~Brett

I just chrono'd mine today.

New Lapua Brass
Federal 210M Primer.
43.5 gr Varget
175 SMK
Remington PS-1 barreled action (PSS with factory DBM)

2600 fps

 

[Surgikill]

Agree with what you stated but he is limited by range.

Could use a chrono and calculate your SD as well.

It was really consistent. I think the most extreme spread I saw was 20 fps. At 43.5 grains I got, in this order from a cold barrel @ ~90 fahrenheit, 2799, 2787, 2786, 2802. ES of 16 fps, don't know how to calculate SD.

 

[Pinecone]

SD calculator

Standard Deviation Calculator - Calculate mean, variance of the numbers

For that string, SD is 8

 

[Surgikill]

Not that bad then for factory second bullets and lc brass.

Sent from GS3 Synergy

 

[Xtremegunnr]

Sorry if i comment on something that has been mentioned. I read the first few posts and skipped down to here. After about 2750 give up on the 175. It is a great bullet for tactical comp at UKD but at the longer distances it still drops off quite quickly. There are bullets with similar BC that are lighter (155 grainers) and many with WAY higher BC in the 195 to 215 grain range. With a longer barrel like yours i would go with a 208 amax loaded to mag length. Try to get 2600 or 2550 with it and you will be pleased. Just my 2 Cents. I shooot 208, 225, and 230 quit often with great results. They may drop faster than the lighter bullets but they buck the wind well, stay supersonic for a much longer distance, and hit like a ton of bricks. Have a good one

 

[Surgikill]

Sorry if i comment on something that has been mentioned. I read the first few posts and skipped down to here. After about 2750 give up on the 175. It is a great bullet for tactical comp at UKD but at the longer distances it still drops off quite quickly. There are bullets with similar BC that are lighter (155 grainers) and many with WAY higher BC in the 195 to 215 grain range. With a longer barrel like yours i would go with a 208 amax loaded to mag length. Try to get 2600 or 2550 with it and you will be pleased. Just my 2 Cents. I shooot 208, 225, and 230 quit often with great results. They may drop faster than the lighter bullets but they buck the wind well, stay supersonic for a much longer distance, and hit like a ton of bricks. Have a good one

I want to give that a try but my twist rate is to slow for that I think. Hopefully tomorrow I can load some up and see what does what.

Sent from GS3 Synergy