Min velocity for Rams w/ 168gr SMK in a 7-08

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Min velocity for Rams w/ 168gr SMK in a 7-08

Post by bugabob »

Tested several loads in my 7-08 w/ 24" barrel using Varget, Rem and Win cases, CCI 200 primers and the 168gr SMK. Most accurate was 36.0gr of powder - 5 shot group 2.23" at 300 yards (benchrest range only goes out to 300). Next was 38.0 gr - 2.6". Shot into a 10-15mph gusting north headwind that occasionally shifted out of the NNW.

Also shot 39.0 and 40.0 grains w/ the latter being the worst at approx 4.6".

Hodgdon's reloading data center shows 37.5 gr of Varget pushing this bullet at 2430fps. 40 grs 2540fps. I don't have access to a chronograph and wonder what kind of velocity I'm getting with my lighter load and if it's enough to reliably knock a ram over. Did a search of this website and believe the lightest ram load mentioned was 37.0 grs being used. Seems like someone said you need a minimum velocity of 2350(?) for rams. FYI - I will be shooting 40.0 gr of Varget w/ 130gr SMK's for C, P and T's but have never shot in a match (the nearest sanctioned match is over 200 miles away).
Would appreciate any thoughts. Thanks.

Bob
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Bob Mc Alice »

My guess is you will reach 2350 to 2390 FPS with 36.0 grs. Varget. I will take that accuracy over the others you mention. Even the 38.0 gr. load is very good accuracy for the conditions you had.That accuracy should hold up well just going another 200 meters. You should knock over most decently hit rams with it. Plan on losing one now and then, we all do. No doubt your elevation turret will be at or just over a full turn from chickens. Your 40 gr. load with the 130 MK is on the fast side, probably approaching 2775 FPS. But if it's accurate by all means use it.
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by bugabob »

I have a Hart SS barrel that was installed almost 30 yrs ago and I'm not sure of the twist rate. The 40gr Varget load w/ 130 SMK's is the most accurate. Believe me, I sure would prefer a lighter load. If the 36gr/168 SMK holds up with further testing I may switch to it for all animals. Less powder and the bullets are about the same price.

Checked seating depth using the slotted case neck method and the COAL averaged 2.860" with the 168gr just touching the lands. Seems long and I forgot to see if it'll still chamber a round from the magazine. Will check that this weekend although a 15-25mph wind is forecasted. We have a HP silhouette range at my club but only pistols and black powder matches are held there. Just very little interest in HP rifle matches. Will ask if the BP guys will let me shoot with them in a match. I'm glad to at least be able to practice on the swingers out to 500M.

Double checked and I believe the nearest sanctioned HP match is over 300 miles away. Bummer.
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Bob Mc Alice »

I shot three matches with our IHMSA long range pistol guys in the past. They were always amazed that I could hit half or better of my targets...standing up. :) It is a real shame to have a HP silhouette range not used by rifle shooters. You should get a badge that says "Match Director"and try to revive the local interest. Heck, I know several Colorado yahoos that would gladly make the 600 mile trip to shoot your range. On the other hand, come out to our State HP in September. It will be a 2x60 format this year on the Sunday after Labor Day. I will waive your entry fee. You can camp at the range or take advantage of the deluxe accomidations in the nearest town 20 miles away. :ymsick:
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Snake »

OKC was a great HP range. shot on it years ago when Bill Smith (aka GRIZ) ran the match. I use 37 grs of Varget or XMR 4064 with 150 MKs, 168 MKs and 175 MKs... the 175's get over 2450 with a Federal primer (the CCI's are great with new brass but too hard for used stuff) ..Win brass. but I have a .310 neck so the brass is all turned to .011. The Brass actually out lasts the barrel ( average barrel life about 7500-10000), the 3 groove 8 twist Pac-Nors survive the longest...the 8 twist Shilens not long lived but like all shilen's they shoot great and break in fast. At our last 600 yd benchrest match I used my silhouette rifle (bad idea...doesn't ride the bags well enough). I shot a 2.8 inch group (5 shot) with 150's over 40 grs Varget......I placed 8th with that group! The winner used a 30 BR and his group was under 2"...YIKES :shock:
I think i'd check the throat on that Hart...and maybe chase the erosion (seat my bullets further out and add more powder to balance it out).
The 168 7mm seems to work best at about 2500---
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by edgehit »

A 168 SMK with MV of 2500 will hit ram line at 1635fps according to JPM ballistic calculator. This will give you 1.22lb-sec momentum =1635x168/226000. Should be plenty of whomp!
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Joaquin B »

I use 38.5 grains of Varget in my 7-08 Tikka with the Sierra 168s. MV is 2550 fps. Brass is Winchester and the primers are Federal 210M.
Every ram hit has gone down, so far.
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Bob Mc Alice »

edgehit wrote:A 168 SMK with MV of 2500 will hit ram line at 1635fps according to JPM ballistic calculator. This will give you 1.22lb-sec momentum =1635x168/226000. Should be plenty of whomp!


The Sierra ballistic table shows a 168 7mm MK launched at 2500 fps is still traveling at about 1800 fps at 550 yds. Remaining energy is about 1200 ft.lbs. Yep, that is plenty of ram stomping whomp. With the right hit and right ram. I lost one in AZ at 2600 MV hit square in the center butt. :?
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by cslcAl »

I used to shoot 7-08's back in the last century. I caught the 260 bug in 2002, but this year I have broke out my old 7-08 hunter rifle. It's a strange looking rig. It has a 24" number 3 Krieger chrome moly bbl. in the white ( 1-8.5 twist ), bolted into a Remington Classic wood stock. That's right I said wood. There are actually silhouette shooters who have never seen a hunter rifle like this. Nuge, Nuge. Don't be alarmed I also have two full blown MODERN 260's #5 Kriegers in Neisika Bay stocks.

Anyway this post prompted me to do som chrony work with the old 7-08. I have over the years lost a fair amount of rams with several '08's using 168 SMK's. I shoot a lot at Ridgway, and anyone who has been there at Nationals knows thier rams can be tough. The ram load I used for years is 168 SMK with 39.0 grs. of IMR 4064. Fed 210 primer. I chronographed this load today at 2498 fps. Using the Sierra V6 program this gets 1049.2 ft/lbs. of energy with 1.25 Lb/sec. of momentum at 500 meters. Looks good on paper, but like I said I lose rams from time to time. NOT acceptable.

Now I also had the oppertunity to shoot the 175 SMK at Raton I think it was in '04 before they were actually released to the market. I didn't get to do a lot of testing as I had a limited quanity, so I just used my 39.0 grs of IMR 4064 and went off to NM. It was truely amazing how hard they took down the rams. Also I got on the rams with fewer clicks, I think it was at least one minute. Today I also chronographed this load shooting paper at 200 meters. I shot a nice 1 1/2 in. group ( this rifle has close to 4k down the bore also ) at 2462 fps. This relates to 1228.3 Ft/lbs. of energy and 1.38 Lb/sec. of momentum. That beats the crap out of a 168. I loaded some up to try Sat. at our HP match at CSLC.

I also tried some with 39.0 grs of Varget. They grouped as good as the 4064 load, and the velosity was 2 fps faster. It had a lot more muzzle blast and was not real pleasant to shoot.

I'll report back after the match. Hope I can hit some, we'll see.

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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Bob Mc Alice »

Al, I was the guy that gave you the packages of the not yet released 175 MK's Tommy T. was passing out for testing. He said an 8 twist was recommended but I got some any way. Before I left Raton I gave them to you after hearing you had a tighter twist rifle. I did test some a few years ago but my 9 and 9.25 twist guns can not do better than 6 inches at rams.
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by cslcAl »

Bob,

I remember that. Believe it or not the bullets I was testing today were those bullets. I had to break into some new green boxes to load for the match Sat. I don't like going to a match with the thought of losing rams in the back of my mind.

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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by cslcAl »

Shooters,

I shot the 175 SMK's mentioned above at the CSLC HP match last Sat. I managed to hit 5 and they went down with much more authority than my 168 SMK loads. There was some wind and I heard others saying needing at least 2 min. I only needed 1 min.
Test over, 175's forever.

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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Bob Mc Alice »

Good to know your eight point five twist shoots them well and puts them down. Us poor slobs with the slower nine plus spin rate do have a decent alternative, though. The 175 Hornady Interlock is accurate in my guns and knock them over, too.
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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by cslcAl »

Bob,

I always wanted to try some Hornady's, but I'd have to buy new clothes to wear to the range. If you know what I mean.

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Re: Min velocity for Rams w/ 168gr SMK in a 7-08

Post by Snake »

MCAlice & Al....you fellas know that Sierra now makes 180gr 7mm MKs ? An 8.5 twist or faster is probably a good idea (Greenhill formula says so). And Bob...that AZ ram you lost...was that another 130gr ding? :D :D
The question was whats the minimum velocity for 168's? In the mouse guns BR, PPC TCU 2350 seems to work just fine :?
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