6BR velocities... what I see vs. what I read...

[memilanuk]

Al,

Well, we might be at an impasse here... the whole 'point' of this gun as originally conceived was as little 'gunsmithing' as possible. Didn't exactly plan on winning BR matches w/ it, granted, but didn't figure on being 200-300fps shy on muzzle velocity either. The issue isn't so much the money as the months and more months w/ no gun. Weeks I can handle. Months I start geting irritable quick-like.

It's been thru Fred Moreo's shop; if you have someone in mind who knows more on 'fixing' the bolt timing and cam angles on a Savage... speak up man and let me know Might have to give them a call. He trued and timed it, significantly reducing the bolt lift as compared to the factory. The action has been trued...so the bolt lugs should be mating up fine. Maybe not BR grade... might have to explain the difference there for this in-the-dirt shooter. Bushing the firing pin hole... well we've got an up-n-coming BR smith up north of here a couple hours who's supposed to be a pretty hot ticket according to our local Hunter BR guys. Maybe I'll see what he can do. Again, I'm not getting any kind of primer sign yet, much less blanked primers, so I'm not sure what kind of meaningful difference it will make at this point. I may change my tune on that once I fiddle w/ jamming the bullet some as Paul mentioned.

Thanks,

Monte

 

[BillDorsey]

Milanuk, If you get it to the point where you're happy with it and you start popping primers...like I do with my old Shilen action BR rifle. It loves a hot load, but it's 40 years old and I don't want to bush the firing pin hole. Go to CCI primers and keep on going. This little switch has relieved the blown primer headaches.

You do say that you're not even seeing primer pressure indications yet...maybe you're looking for something to go wrong when it hasn't. When it does, look for the solution.

Maybe I've been shooting Benchrest too long, but until I see some primer cratering, I'm not sure I've got enough powder in the case.

Bill Dorsey

 

[AlNyhus]

Hi Monte.

I had spent about 45 minutes typing a long, detailed reply on this subject but when I went to 'preview' it, it gave me a blank screen with a 'page expired' note at the top and lost all my work. aarrggg!

So, I'm going to post two pics of a case in my Panda bolt. Hopefully you'll see where I was going with my case head-bolt face comments, exaggerated as my photos may be...you'll get the idea. Good to hear that the bolt is camming correctly..one thing to not worry about.

P.S. The case is not a 30BR. -Al

 

[chris308]

Lynn, my first fast twist br was throated so a sierra 107 had most of the boat tail in the shoulder area.About 2740 was this highest i could go.I switched to a berger 95 vld and the boat tail is inthe neck area.I may have lost a few points in the b.c. but picked up 350fps EASY.I also noticed it is not as picky on powder preference.30-31 grs of vv n140/n150 very accuarately.

Lynn,i sent a dummy cartridge to PT&G to have a reamer cut.The sierra 107 is seated with the bearing surface/boat tail junction 1/2 up the neck.The print shows .134 freebore.I should get 2900 fps out of this combo don`t you think?
chris

 

[AlNyhus]

Monte; If you're willing to do a bit of tinkering, I can let you know what I did with a couple of Savages to identify the causes of the problem you're describing. It's easy to do, doesn't cost hardly anything and can be done in an afternoon at the range with no permanent alterations to the gun.

Jeez...I sound like that Billy Mays guy from the TV infomercials! "Hi. Billy Mays here for Oxy Clean..I mean, Savage Rifles." :lol:

 

[memilanuk]

Well, I shot up most,all but three) of my loaded stuff yesterday in another F-Class match... did pretty good but couldn't see the mirage for squat,overcast day) and the wind was switching around just enough to cause me grief,occasional 10's). So on the one hand... I'm a little reluctant to mess w/ a load that works. On the other hand... I can always go back to it for the next match,probably close to a month or more away). In other words... I've got a little time to play, especially in the next couple weeks: 'only' eight hour days 0600-1400 Mon-Thu, then off til Friday night of the following week. Of course, there's the inevitable honey-do's that interfere w/ range time,and I need to start cleaning the gun range as well for the spring matches)...

Anywho... suggested first course of action? I'd considered taking the existing load of 29.5gr Varget, Lapua cases, and CCI 450's and varying the seating depth from -0.030",30 thou off the lands) to +0.030",30 thou into the lands) in 0.010" increments, and run them over the chrono to see if there are any noticeable changes just from that one variable alone. The catch is I think I'm going to have to increase the neck tension some, as right now if I push hard enough I can push the bullets into the case a little,i.e. I wouldn't consider them to have enough tension for Service Rifle RF stages) and jamming into the lands will most definitely seat them in, negating the purpose of seating them out, right?

Thanks,

Monte

 

[Forum Boss]

Monte,

FYI, my Redding die, honed at the neck, leaves the brass .268 after sizing. That provides enough tension to seat .025 into the lands without bullet movement in my Savage.

You can do a simple test by loading a dummy round,no powder), then putting the case into the chamber and measuring the OAL before and after. The scuff marks will also give you a clue as to whether the bullet is moving.

If you have a bushing die, I can lend you a .266 which should give heaps of tension.

 

[memilanuk]

I have the bushings, just been using a floating carbide expander ball on my Redding Type 'S' F/L dies as I seem to be one of the more fumble-fingered souls around... seems like about once a loading session I drop a case on the floor,concrete) and of course Murphy's Law says it must always strike on the mouth of the case at the correct angle to do maximum dentage... particularly if the case is already primed. Sheesh.

I'll set up the Redding body die,due for F/L sizing anyway... bolt is getting a little hard to close now after 3 firings or so) and haul out the Wilson dies and arbor press. Probably better set up the KM ExpandIron mandrel too while I'm at it

Just out of curiosity... earlier a comment was made,Lynn?) about F/L sizing being a culprit of lost velocity vs. neck sizing... someone care to explain that one to me?

Thanks,

Monte

 

[Forum Boss]

If you full-length-size you will bring in the body diameter a little bit, plus move the shoulder down a little bit. This reduces case capacity. Less case capacity = reduced velocity potential.

I'm sure it has an effect, but all the velocity numbers I've given you are with case FL-sized in a Redding die. It would be interesting to just neck-size a case and see if I can load it hotter. But right now my FL,honed-neck) die works so efficiently I'm not inclined to mess with bushings. Also, even after FL-sizing, my case capacity is 38.40 grains H20, which is still larger than an unfired case,37.80). Unsized, after firing, the case capacity is 38.80 grains.

QuickLOAD suggests that comparing 38.80 capacity with 38.40 capacity, using Varget, I could load about .25 grains more for the same pressure with 38.8, and pick up about 10 fps.

For me, that's marginal so I'll keep FL sizing since the results have been good and I think it keeps the cases more uniform.

 

[memilanuk]

Well, finally got to the range w/ those test rounds today...

Five each of -0.030",30 thou off the lands), -0.020", -0.010", 0.000", +0.010", +0.020", and +0.030",30 thou into the lands). I bumped the shoulder back a couple thou because it was needed,used a Redding Body die), put a .267" bushing in the Wilson neck die and sized the rounds, charged them w/ powder,29.5gr Varget), and then seated using my Redding Competition seater,it appears that my Wilson seater doesn't play nicely w/ the long 107gr SMK... it bottoms out on the tip rather than the ogive).

The average velocities jumped up to about 2750-2760fps, but I think that was more due to the neck tension than anything; it didn't seem to follow any other sort of trend as the seating depth extended. From -0.010" on there was light cratering of the primer. +0.020" seemed to be the next tightest grouping after the original load,-0.020" and much less neck tension). I'll see about loading up some rounds at that seating depth w/ some small steps in the powder charge and see what I can see tomorrow or the next day.

 

[Forum Boss]

Monte,

With a Savage, you WILL see cratering of the primer even with a moderate load. This is brass flow around the firing pin tip. If the edges of the primer are still round the problem is not pressure per se, but the excess clearance around the firing pin. Bushing the firing pin is the answer to that. But I haven't done that on my Savage.

Re the Wilson, I'm not sure what the problem is, but mine seats the 107s just fine. There is a set screw that allows you to move the seating stem up and down. Maybe yours wasn't ground right.

Watch the edges of the primers and look for bright ejector flow on the case head--That, and loose primer pockets, will give you your upper limit.

 

[memilanuk]

Well, getting the Wilson 'fixed' ain't a big deal... they're about a half hour away so dropping it off at the shop,and one of the gunsmiths I frequent has his shop right back door to Wilson's) is no problem.

As far as the pressure sign... honestly, I'd just as soon *not* loosen primer pockets... as far as I'm concerned, I've got a reasonably 'matched' set of cases that work well in this gun and I don't want to start thinnin' the heard un-necessarily... might happen anyway, but if I run into that, I done went way too far as I see it. Right now as it sits, I'm a bit shy on cases to make it thru a three-day match w/o reloading as it is.

Either way... the 'original recipe' seems to be pretty tough to beat; although I must say the 'challenger' looks to have promise:

 

[Forum Boss]

Monte,

Thanks for posting those targets. We are constantly being asked "should I jump my bullets or jam them?". You've just proven that both options can be very accurate. I personally jam my bullets about .015 because I've been able to achieve the best velocities without stiff bolt lift that way.

But my Freebore is about .080. If I had a .120 Freebore, I'd experiment more with jumping.

With my 30.5gr jammed load recently going 1.6" at 610 yards I'm pretty happy.

As others have noted if your "slow" load is delivering superior accuracy and you are happy with your match performance, there's no need to change. This exercise can help show people how to achieve more velocity.

FYI, I just looked at my primers. There was the same amount of cratering on the factory ammo,2830 fps) and with my 30.5 Varget load,2920 fps). It's a firing pin thing.

In your situation I'd go ahead and load three +.015 jam cases at 30.0, three at 30.3, and 3 at 30.5 and see how it goes. Run them over the chron and tell us the results.

 

[memilanuk]

Well, took the Savage to the range again today. For those just joining us, the rounds were 107gr SMK's in Lapua brass, lightly neck turned, CCI 450 primers, Varget powder, bullets seated 0.020" into the lands. Barrel is a 27" SSS/Douglass barrel, .272" nk, 1-8" twist w/ about 600rds thru it. The 'known' good load is same bullet, 29.5gr Varget, 0.020" *off* the lands... shoots great, but goes 'only' 2700fps, now 2750-2760fps w/ some increased neck tension.

Today's run:

29.6gr.....2780/2759/2800
29.8gr.....2796/2792/2800
30.0gr.....2807/2811/2797
30.2gr.....2807/2797/2804
30.4gr.....2811/2820/2812

The groups were tighest around 30.0-30.2gr... but the primers craters are quite puckered and raised. Even w/ no sticky bolt... I honestly don't think <100fps is worth the hassle over the 'control' load, and w/o bushing the firing pin or doing something, I don't think I care to push any harder w/ this bullet/powder/primer combo, regardless of seating depth. I'd hoped to maybe hit another velocity plateau a couple hundred fps above where I was... but it looks like those who predicted the firing pin hole on the Savage to be a limiting factor were right. We have a good BR smith a couple hours away and I could send the bolt head off to get 'fixed. I may consider it, but it's getting kind of close to match season now.

Hope this helps someone.

Monte

 

[memilanuk]

Basically, when the bullet goes thru the paper it 'stretches' the fabric of the paper slightly... if you smooth out a target sheet and measure the outside of the 'burn' marks of an individual bullet hole, it is very often *not* the same as the actual bullet diameter, but some smaller value. This is one of the reasons for the stiff almost card-like material used in some more 'formal' targets... it tends to cut a clean hole of accurate size.

In this particular case, one individual hole in this target material from this bullet measured .206"... just calling the hole size .243 would have given a potentially inaccurate,too small) group size.

A touch geeky, but it's what I was taught

HTH,

Monte

 

[Forum Boss]

Monte,

Thanks for taking the time to try the jammed loads. I thought you could get to 2850, but it might take RL 15 to get there, and I bet the Scenar 105s would run a little faster in your barrel.

We have learned three things from the exercise.

1. Longer seating may indeed permit higher velocities.

2. A bushed firing pin can be important to get max performance from a factory action.

3. There can be significant velocity variations from barrel to barrel. That's why I encourage everyone to buy a box of the factory ammo. The factory-loaded 105s ran 2780 from Jackie's Krieger with 60 deg temps. They ran 2830 from my PacNor with 80-deg temps. We'll soon have data from Jason's Broughton. That gives us a baseline to judge the relative speeds of various barrels. I think your barrel IS on the slower end of the scale.

Your conclusion about sticking with the original load makes sense, and I bet your brass will last a LONG time. But at least you were able to establish that a higher V is possible.

 

[memilanuk]

Hope you guys don't mind me dredging this thread backup... shot my Salvage 6mm BR @ 800/900/1000 this weekend, both days in a match. The gun shot well, but man was that wind kicking my hiney. The 'other' F-Class shooter was running a full-custom 6.5-284... and lets just say it wasn't all that close of a race :, 600 and in, maybe. 800+... don't think so, not on this range.

Anywho, back to the point... spent some time in the pits and between relays picking the brains of some of the assembled HM's and whatnot... more than a few had shot multiple 6mm BR's, and seemed to advocate *not* jumping the bullets, and running them quite a bit faster. Hmmm.... been down this road already, I think. But they suggested another possible route... primers. Right now I'm using CCI 450's... anybody believe that I'd see any potential improvements going w/ BR4's, WSR's, FGMM 205M's, 7-1/2's, etc.?

TIA,

Monte

 

[slappomatt]

hardly an expert on the matter but what I've heard,mostly from here) is that the BR4's are simply hand inspected cci450's so no velocity differance should be there. and I've heard that the 205's are softer so you should get cratering sooner, but that the 7 1/2's are a little harder so you might be able to load a little hotter. I have only shot 405's in my rem 700.

I was having some primer blanking but after having the fireing pin bushed it hasnt happened again. btw im getting ~2830fps with a 28" pac-nor 8twist .272, 30grains varget w 107's and virgin lapua, CCI450's.

 

[memilanuk]

Okay, time to confess and repent...

This has been an ongoing sore spot for me. Don't get me wrong, the gun and load I have shoot very well, and have done fairly well for being of humble origin. The gun goes bang every time I pull the trigger,bonus) and the load will put them in groups smaller than I can hold in 600-1000yd F-Class. The wind does blow a bit at some of the ranges around here, so a wee bit more oomph would certainly be welcome in reducing the amount of hold off in the wind.

A fellow shooter recently got a 6mm BR w/ a Krieger barrel, and ran into the same 'wall' I had... 2700 fps, give or take a bit. Stellare accuracy, but considering some of the claims one reads on the Internet, it leaves a person feeling a bit cheated in the speed department. All the 'arguements' about why this was taking place just didn't seem to validate 250-300fps worth of speed differential, at least not in my mind.

As a last resort, we decided to take the Moderator's advice and order some Lapua factory ammo for some benchmark reference testing. Shortly after placing the order, we concurrently,w/o knowing the other was doing the same thing) broke down and started tipping the jug o' Reloader 15. Actually, I think his earlier load *was* w/ RE-15, but a different lot. Anywho.

To say the results were a bit eye-opening is an understatement; the speed was there right off the bat. The accuracy is another subject, though. The 'best' group w/ the RE-15 would probably only qualify as a mediocre group ww/ the Varget load... albeit about 200fps faster. I haven't fully explored all the options here to find what RE-15 likes; still using CCI450 primers, 107gr SMK's seated 0.020" off the lands,seems to work best w/ MK's in general, and this gun in particular... others I know have different results), cases F/L sized in Redding Type 'S' bushing die, seated w/ Redding Competition seater, charges weighed w/ a AccuLab VIC 123 milligram scale.


Charge MV,Avg) E.S. S.D. Comments
29.00 2683 21 7.5 10 shots,sighters), 2nd best group,s)
29.30 2721 8 4.0 5 shots
29.60 2738 11 4.8 5 shots
29.90 2771 10 4.3 5 shots
30.20 2788 28 11.2 5 shots
30.50 2800 28 10.1 5 shots
30.80 2871 1 0.6 5 shots,only 3 recorded), best group
31.10 5 shots, none recorded
31.40 2925 14 5.8 5 shots
31.70 2986 5 shots,only one recorded)
32.00 2975 18 7.2 5 shots

Bad day, or at least afternoon, for precision electronics and me. Scale was going bonkers half the time,solar flares, dunno, beats the heck out of me), *very* frustrating and time consuming weighing out these 25rds. Weighing charges is teeth-grindingly aggravating to begin with, then when your ~$300 precision milligram scale starts acting retarded and the NiMH battery for the IR skyscreens on the chrono goes T.U. the day gets worse exponentially…

Anywho, finally have some slight pressure sign, a bit o' crater on the primer. Actually around 30.50-30.80 it's there if I look w/ a jeweler's loupe or scrape just right w/ a finger nail. By 32.00 it's definitely there, but no worse than I was getting w/ my 'normal' load of 29.6gr Varget. Bolt lift was 'firm' towards the end, but not what I'd call sticky. Ambient conditions were about 81°F, 30% RH.

 

[Forum Boss]

Monte,

If the accuracy isn't there,yet) with the RL15, I suggest you go to .015" into the lands. Most of the guys I know who are shooting consistent 1/4 moa or better are .010" or more into the lands. Jason's at about .017" I think with his CR 106s. Terry Brady just shot a .645" 5-shot group at 600 and he's WAY into the lands with Berger 105s.

Moving your bullet .035" inwards,from .020" out to .015" in) from your current position will also create a little more boiler room, but jamming will also raise the start pressure. I suggest you back off your "max" load by 1/2 a grain then work up again.