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FN SPR 284 Win - short action

turbo54

turbo54

Mr. 7mm
Full Member
Minuteman
Dec 10, 2010
4,995
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Michigan
Well, it took much longer than I thought/hoped...but it's together, ready for some barrel breakin/ladders, prior to the barrel going off for Melonite.

Specs:

FN SPR CRF action
Chambered in 284 Win "match" with .317" neck and .088" freebore
McM A4 stock with Joe Ducos (stockdoc) pre-loggerhead cheekpiece
Bartlein fluted M40 measures 25.5" from face of action to crown - barrelwork performed by Bartlein
APA little bastard brake
CDI bottom metal
Alpha type 3 and type 4 magazines
Jewell trigger
Tubb speedlock firing pin and cocking piece
NEAR 20moa base
Farrell 34mm rings
Premier 5-25

I'll be sending the barrel off for melonite, and the action/base/rings for ionbond next week. I'll do my stock finishing work and final de-wax (from bedding) while those parts are away.

Other than the chambering/crown, I ended up building this myself because I didn't like the timelines from smiths. Next time, I think I'll chamber it myself to further improve lead time. I'm not a big fan of waiting...and waiting....and waiting.

The CDI bottom metal required a little machinework to the receiver, which actually worked out well, as I was able to make the magwell in the receiver *just* right for the magazines, eliminating most of the rattle/wobble common to many DBM setups. I used a 3/16" ball-nosed endmill and it came out real nice. I haven't felt a rifle whose DBM fits and locks up as solid and nice as this - I'm a big fan.

I thought I'd need to perform some surgery to either the bolt stop, ejector or ejection port to be able to extract/eject a live cartridge, but I didn't. At 2.950" COAL, they come right out perfect!


It was my intent to have the muzzlebrake contoured with the barrel, so that the barrel/brake formed a long, smooth taper from action to crown - but that got lost in translation. I'm still deciding if I want to turn the brake down before it all goes off for Melonite ...any thoughts on that?

My primary intended bullet is the 162 Hornadys, but this will mag-feed any high BC bullet except the Berger 175 XLD and probably the new Berger 195 OTM. I'm expecting 2950fps with the 162, and hoping for 3000fps. Guess we'll see!

Without further adue:

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Re: FN SPR 284 Win Build Complete (pretty much)

That turned out really nice, looks like a keeper.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Very nice indeed and an awesome action to build on.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Nice bedding job, I'll be interested in seeing how it performs.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Very nice! I like the brake contoured to barrel, just my preference. I just like the clean, one piece, look of a barrel with brake.

Nice rifle though, let us know how it shoots.
 
Re: FN SPR 284 Win Build Complete (pretty much)

The rifle shoots nice, but light wasnt right for the chrono today, so I got no velocity data.

I ran some very coarse ladders with H4350/162amax and RE17/162amax. I didn't find the limit with either, loading up to 54gr of each.

I also shot 10 rounds of 52gr RE17/162amax, which I've seen a number if folks claim shoots well. I'm not very good shooting off the bench with a bipod, but still managed a 1.5" group at 200 yards. 7 of the shots were a single ragged hole that was about 1/4 moa, but the other 3 were certainly fliers. Again, I'm not great off tge bench with bipod, and with my other rifle, can certainly hold 1/2 moa prone, but about 1 moa off the bench.

Bottom line, I'm confident the rifle shoots! Just wish I knew how fast!

The barrel coppered pretty good after each of the first 5 or 6 shots, but settled right down, barely picking any more up after I shot 5 in a row with no cleaning.

Total round count: 24

Now off for melonite.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Looks like some good info. Were your loads at 54 grains compressed? I am glad you had no pressure signs yet. I am confident you will reach 2,900+ with the 162s
 
Re: FN SPR 284 Win Build Complete (pretty much)

At 54gr, there was a slight "crunch", about the same as 45gr Varget/175smk in a 308.

I can definitely squeeze at least 1.5-2gr more in there!

I've had good luck with compressed charges in the past, and you can squeeze more into a case than you might think. My 155 Scenar load for my 308 is 49gr Varget, and that is nearly up to the brim...makes a nice "crunch" when you seat the bullet, and goes 2975fps from my 24" Savage.

I was bummed by the chrono - but VERY happy to see my mega-short throat didn't show pressure right away.

I agree, I think 2875+ with H4350, and 3000+/- with RE17 is gonna happen. "Sandwarrior" here on the hide claims he's tested RE17 from -15°F to 100°F, and it is AS stable as Varget.

Life is good.
 
Re: FN SPR 284 Win Build Complete (pretty much)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">At 54gr, there was a slight "crunch", about the same as 45gr Varget/175smk in a 308.

I can definitely squeeze at least 1.5-2gr more in there!

I've had good luck with compressed charges in the past, and you can squeeze more into a case than you might think. My 155 Scenar load for my 308 is 49gr Varget, and that is nearly up to the brim...makes a nice "crunch" when you seat the bullet, and goes 2975fps from my 24" Savage.

I was bummed by the chrono - but VERY happy to see my mega-short throat didn't show pressure right away.

I agree, I think 2875+ with H4350, and 3000+/- with RE17 is gonna happen. "Sandwarrior" here on the hide claims he's tested RE17 from -15°F to 100°F, and it is AS stable as Varget.

Life is good. </div></div>

Hey turbo nice build. I think it looks great, not sure I would mess with the brake I think it is just personal preference.

You mention the very short throat...did you have the freebore set that based on your expected maximum mag limited COAL?

Very interested in your velocities and next range report. Hoping sanwarrior is correct about the temp sensitivity, or hopefully lack thereof, of RL17.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Grate job looks really nice.let see some holes
 
Re: FN SPR 284 Win Build Complete (pretty much)

Chrono worked today... Only tested 1 load though...

162amax, 52.5gr RE17 @ 2.950" COAL - 2948fps average

No pressure signs.

Life is good.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Update:

Rifle is FINALLY "done"... I ended up turning the muzzlebrake down to form a continuous taper with the barrel. Because Karl Kampfeld is a friend, and local, I had him re-flute the barrel with REAL flutes. Bartlein makes a great barrel, but their flutes are weak. I also had Karl do a Badger bolt-knob conversion. Then I sent everything but the springs of the entire rifle out for melonite. Looks great.

Load development the last 2 weeks has been rough... I know Reloder 17 provides speed, but between poor accuracy claims and temperature sensitivity claims, I wanted to get a Hodgdon extreme powder to work. I began with H4350 and had nothing but problems. Poor accuracy and EARLY pressure. I wasn't expecting that. We're talking 2825fps with 162s with an ejector mark, and 2785 with a 180smk with ejector marks.... dogshit.

I had, many months ago, done some experimenting with H4350 and H4831sc to see how much I could fit, with a max COAL of 2.950". To get enough H4831sc in the case to come anywhere NEAR the 284 loads others are getting good velocity from, I had to massively compress the charge. We're talking 53gr is max non-compressed, but others with LA 284s are up around 57 or 58gr!

So, with H4350 an epic fail, I tried H4831sc today. Ran ladders at 600 yards from 54-58gr with 162, and 52-56.5 with the 180smk.

Yes, that will fit. You just gotta squeeze it in there... The result? A textbook accuracy node centered around 57gr @ 2975fps (calculated based on .G1BC = .61, doped at 600 yards). The target spot is 3" diameter...

1339635624.jpg


The 180smk ladder needs more development, not as textbook, but based on a G1BC of .65, it is going 2850.


I had zero, zilch, nada in the way of pressure signs today. Primers look textbook, nice rounded corners, no ejector marks and easy/smooth bolt lift.

Todays data indicates to me that (perhaps) the SA 284 gives up no performance to a LA 284, if you simply compress the charge.

More to follow...
 
Re: FN SPR 284 Win Build Complete (pretty much)

Nice thing about the 180smk in 7mm, is the ogive is rather short - so it fits well in the SA 284.

That said, the 162@2950 outperforms the 180smk@2850. I think the 180 starts nudging the 162 out on drift way out there past 1000.

I'm thinking the 168 berger is probably the highest performance bullet for this package. Ive got some to try, we'll see how it goes. I'm nit too interested in keeping VLDs "in tune" though...
 
Re: FN SPR 284 Win Build Complete (pretty much)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bward</div><div class="ubbcode-body">The 162 is a vld. </div></div>

True... But the 162 isn't known to be a bastard, and the Berger VLDs are.

Gotta admit though, I'm speaking 75% hear-say. I've mainly used Tangent ogives, but the .224" 80amax, and .284" 162amax have both been pretty easy for me to get worked out in several rifles. I admittedly have never loaded Bergers...though it seems I've read/heard lots of bitching about their VLDs.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Turbo,
Good looking rifle. I built a .284 on a pierce S/A in a tube gun.

I have been testing the 180 bergerhybrids and the 168SMK's.

Here's what I have come up with so far.

180 hybrid
55.5g 4831SC
2842 AV

168 SMK
56.3 4831SC
2936 AV

I could go hotter but these provide good accuracy.

How much freebore and what is your neck dia on your reamer?

KT
 
Re: FN SPR 284 Win Build Complete (pretty much)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">Update:

Rifle is FINALLY "done"... I ended up turning the muzzlebrake down to form a continuous taper with the barrel. Because Karl Kampfeld is a friend, and local, I had him re-flute the barrel with REAL flutes. Bartlein makes a great barrel, but their flutes are weak. I also had Karl do a Badger bolt-knob conversion. Then I sent everything but the springs of the entire rifle out for melonite. Looks great.

Load development the last 2 weeks has been rough... I know Reloder 17 provides speed, but between poor accuracy claims and temperature sensitivity claims, I wanted to get a Hodgdon extreme powder to work. I began with H4350 and had nothing but problems. Poor accuracy and EARLY pressure. I wasn't expecting that. We're talking 2825fps with 162s with an ejector mark, and 2785 with a 180smk with ejector marks.... dogshit.

I had, many months ago, done some experimenting with H4350 and H4831sc to see how much I could fit, with a max COAL of 2.950". To get enough H4831sc in the case to come anywhere NEAR the 284 loads others are getting good velocity from, I had to massively compress the charge. We're talking 53gr is max non-compressed, but others with LA 284s are up around 57 or 58gr!

So, with H4350 an epic fail, I tried H4831sc today. Ran ladders at 600 yards from 54-58gr with 162, and 52-56.5 with the 180smk.

Yes, that will fit. You just gotta squeeze it in there... The result? A textbook accuracy node centered around 57gr @ 2975fps (calculated based on .G1BC = .61, doped at 600 yards). The target spot is 3" diameter...

1339635624.jpg


The 180smk ladder needs more development, not as textbook, but based on a G1BC of .65, it is going 2850.


I had zero, zilch, nada in the way of pressure signs today. Primers look textbook, nice rounded corners, no ejector marks and easy/smooth bolt lift.

Todays data indicates to me that (perhaps) the SA 284 gives up no performance to a LA 284, if you simply compress the charge.

More to follow... </div></div>

Nice set up but I will make one comment about our flutes being weak.

We have a min. spec. for flute depth that we run on our contours. Why? It is known that the deeper you go on the flutes you can start effecting harmonics which will in turn effect accuracy.

On a straight taper barrel with like a .900 muzzle we will not go deeper than .100 on flute depth. In testing it has been found that going deeper on a contour like that it can start having a negative effect on accuracy.

Will it effect every barrel? Not necessarily but with what we found in working with one of the gun manufacturers we came up with a set of standards/guide lines that we follow here.

Smaller contours/muzzle diameters we will adjust the flute depth accordingly.

Later, Frank
Bartlein Barrels
 
Re: FN SPR 284 Win Build Complete (pretty much)

Frank: I completely understand your/Bartlein's perspective on deep fluting. I regret any offense in referring negatively to Bartlein's fluting. Y'all are certainly not the only folks that don't like heavy fluting, and I'm certain there is a solud reason for it!

My perspective is that heavy fluting is a risk. You're taking a tube that someone put a lot of effort into getting "just right", and you're cutting on it and inducing stress.

Bartlein has a record that speaks for itself.

Kampfeld has a great record too, though, so having the flutes hogged out was a calculated risk I was willing to take.

Again, I hold Bartlein's product in extremely high regard, and I apologize for putting a negative spin on it. I should have chosen my words more carefully. Sorry again!

Thanks for working so diligently making such great barrels, Frank!
 
Re: FN SPR 284 Win Build Complete (pretty much)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KBT</div><div class="ubbcode-body">Turbo,
Good looking rifle. I built a .284 on a pierce S/A in a tube gun.

I have been testing the 180 bergerhybrids and the 168SMK's.

Here's what I have come up with so far.

180 hybrid
55.5g 4831SC
2842 AV

168 SMK
56.3 4831SC
2936 AV

I could go hotter but these provide good accuracy.

How much freebore and what is your neck dia on your reamer?

KT
</div></div>

KT: What are your COAL's, either to the ogive or head-to-tip?

My neck diameter is .317" (which is a bit tight for Winnie brass), and I've got .088" freebore.
 
Re: FN SPR 284 Win Build Complete (pretty much)

The 180 hybrids are long as crap. I have to single load them. Which is fine for F-class.

180 are right at 3.150 tip to tip.

I will have to go back and measure the 168's.

I'm using a 188 freebore with a .320 chamber. Just to get the bullet out of the case. The loaded round reads 314. That is just lightly turned. I'm using win brass as well. Didn't want donut problems.

A loaded 180 I can't get to eject out of the port but I can drop the magazine and get it out that way.

I was expecting .4 to .6 accuracy due to the bigger round, but to my surprise I have shot a bunch of .1's and .2's at 100.

I will let you know how it does at 1k after this weekend at camp butner.

KT
 
Re: FN SPR 284 Win Build Complete (pretty much)

very nice build, have you done anything to the action??
 
Re: FN SPR 284 Win Build Complete (pretty much)

KBT: Thanks for the info - I look forward to the 168 data. My rifle is mainly intended as a tactical rifle, so it being a repeater is crucial to me... ...thus, I have a HARD COAL LIMIT of 2.975, but practically, COAL should be kept to 2.960 max, to ensure no binding in the Alpha mags.

Loaded rounds in W-W Super brass measure ~.314-.315 UNturned for me. Thats awful tight in a .317" chamber, I think, so I necktutned my WW brass, so it measures .3115-.312 loaded, just like Lapua brass does. If I spec'd a new reamer, I'd get a .320" neck.

Attherange: I did not true the action, because FN does it, and a nice job at that. I measured no more than .0005" out-of-parallel between the receiver face and boltface, and .0005 TIR between the raceway and receiver face.

I did, however, "fluff and buff" the sharp edges and corners on the bolt to smooth out the action a bit, prior to melonite.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Thanks turbo, good to know and again nice build.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Turbo54, Hey man it's cool! Didn't take no offense at all. We get asked the question on a regular basis about how deep can we flute etc...

Just saw an opportunity to talk about it. That's all!

Great looking gun as well!

Later, Frank
Bartlein Barrels
 
Re: FN SPR 284 Win Build Complete (pretty much)

Looks great, man! I am jealous of your velocity. Mine is sloooowwwww! 55 grains of 4831 & 175 smk can just barely break 2700. Hell, my 20" .308 with 175 was nearly that fast. Anyway, you put together a great combo and that SA surely isn't giving up anything to a LA. Nice job.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Turbo54,

Some of the 7mm Creedmoor's we are building are getting 2960'ish FPS with 26" barrels, 162 A-Max, COAL of 2.830".

I know you saw our first prototype at TVP a while back, so I figured I would give you an update on the progress.

Mark
 
Re: FN SPR 284 Win Build Complete (pretty much)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: M.Gordon</div><div class="ubbcode-body">Turbo54,

Some of the 7mm Creedmoor's we are building are getting 2960'ish FPS with 26" barrels, 162 A-Max, COAL of 2.830".

I know you saw our first prototype at TVP a while back, so I figured I would give you an update on the progress.

Mark
</div></div>

Are you still using Varget for that? Incredible speed considering the case capacity! The 7-08 we just set up for my buddy does 2775 with 162amax and 46.5gr H4350 - and I was pretty happy with that.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Mark,

What kind of accuracy were you getting at ~2950fps with that 7 Creedmoor?

You think it could push 180s to 2800?
 
Re: FN SPR 284 Win Build Complete (pretty much)

Mark, you really need to proliferate that 7CM into the mainstream, it is a helluva performer!

Are you willing/able to share either the reamer or reamer print with me? I've got 2 short action 7mm's to set up in the next couple months, and was planning on 7-08AI (don't have the reamer yet), and would LOVE to do the 7CM instead...

...was just thinking that might help the popularization of the cartridge...
 
Re: FN SPR 284 Win Build Complete (pretty much)

We are not using Varget any more. Just not enough bang for the buck with the case capacity.

The latest customer has sent me groups in the 500-600 yard range in the .1's and .2's with the 162 A-Max.

I think if you tried the Berget 180's it would just be a little to big. I designed my reamer to work with the 162 gr bullets. The heaviest one may want to go is probably the 168 Berger.

Mark
 
Re: FN SPR 284 Win Build Complete (pretty much)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: M.Gordon</div><div class="ubbcode-body">We are not using Varget any more. Just not enough bang for the buck with the case capacity.

The latest customer has sent me groups in the 500-600 yard range in the .1's and .2's with the 162 A-Max.

I think if you tried the Berget 180's it would just be a little to big. I designed my reamer to work with the 162 gr bullets. The heaviest one may want to go is probably the 168 Berger.

Mark </div></div>
Mark, what is the recipe you switched to? Or is it a secret?
whistle.gif
 
Re: FN SPR 284 Win Build Complete (pretty much)

turbo, I have a weird question, with your load as it is, can you shoot a 20-22 rds group and still hold 1/2 MOA, I am wondering about powder fouling ruining accuracy for an F class match.
TIA.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Well, something's fishy. Hit the range today with my chronograph, which actually worked today...

162amax, 57gr H4831sc - 2865fps... Not pressure limited, but case volume limited. Even still, velocity stops increasing at about 56.4. 58gr was literally slower than 57.5!

162amax, 51.5gr RE17 - 2890fps... pressure limited, max safe (~90°F today)

180smk, 55.5gr H4831sc - 2835fps... pressure limited, 55.5 is max safe

Not sure how I observed so little drop with the 162 at 600 yards on Wednesday. Litz claims G1BC=.599, Hornady claims .625, I used .610 for calculations. Maybe Hornadys claim is better than Litz?

Anyway, not terribly happy with 2865 when I'm using 57gr of powder to do it. Really irked me when I pulled out the 7-08 I'm working with for a buddy, and 45.8gr H4350/162amax went 2805!

Best I could do in the 284 with H4350/162 was 2825, with 51.5gr... I deduced H4350 was too fast for my application, thus the switch to H4831sc...

Now that I see the 180/H4831 is going 2835, with about 105-110% load density, I think H4831sc is too slow for the 162.

Now, 2835 with a 180 is fine...that makes for good ballistic,s but if the case can do a 180@2835, it sure as hell should do a 162@2900+(++)

Anyone think of another powder to try? Was thinking Vhit n550...though at $31/lb, I'm not sure I'd want it to work!
 
Re: FN SPR 284 Win Build Complete (pretty much)

Ramshot Hunter might be worth a try, it is suppose to temp insensitive.
Contact Ramshot powders for their opinion.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Turbo, the 180 load at 2835 looks awesome. No temp sensitivity with 4831, easy to load smk with nice ballistics, and no pressure issues. Whats not to love?
 
Re: FN SPR 284 Win Build Complete (pretty much)

Update:

My rifle wasn't acting like a rifle with H4350. I cleaned the bore and tried H4831sc. It acts like a rifle, and works nice with the 180s, but is just too sliw for 162s.

I noted, after initial melonite cleanup, there was some kind of "film" in the grooves I couldn't remove. I tested H4350, bad results, but after I cleaned before trying H4831sc, the grooves in the bore looked great.

I decided to try H4350 again. Night and day difference!

I'm now seeing 2850fps with 51gr, up to 3050!!!! at 55gr. 55gr is too much - hope to find accuracy at ~2950 or so with the 162s.

Here is a shot of the chrono at 52gr...

1340144718.jpg
 
Re: FN SPR 284 Win Build Complete (pretty much)

Turbo I have a short action in 284 win too...... I will be doing load development soon too.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Update:

Beware of neck clearance in your 284s, fellas!

My chamber neck diameter is .317". Fired brass measures .315-.316". I've been seeing a lot of fliers, to the point I was questioning if I can even shoot. Also, I've been noticing weird pressure. My initial ladders showed 53gr H4350 to be stout but OK. However, throughout load development, I'll sometimes see signs of pressure with nearly any reasonable charge, from 50gr and up. Sometimes pressure signs were there, sometimes not. Accuracy was poor. I'd stack a few, then drop a shot 3" away (200 yards). I was also seeing poor extreme spread and standard deviation...like ES of 70fps, SD of 15-20...

The necks on my loaded cartridges measure ~.313", which *seemed* like plenty of clearance, but NOT being able to drop a bullet through a fired case bothered me, so I neck turned to achieve .003-.0035/side neck clearance.

This seemed to help the ES and SD quite a bit.
 
Re: FN SPR 284 Win Build Complete (pretty much)

Time for an update again...

Well, the first iteration of this rifle was a fail. Long story short, accuracy was never reliable or consistent. Occasionally, the rifle would print a tight group and show some promise, but next time out, with the same ammo, it would spray bullets all over the place. I finally gave up on the barrel at 549 rounds downrange, and sent it back to Bartlein to check out.

Details here: http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=3466558&nt=2&page=1

So now I've got a Krieger medium palma 8.5 twist on it, chambered with the same reamer. I'd like to point out I've got no bad blood with Bartlein. They were very standup about the barrel, and despite me having two different schmucks do work on the barrel (Fluting and melonite), are replacing my torched one. I hope they are able to learn something of value by dissecting it, so they don't just have to "eat" the cost of my replacement.

Anyway, with 65 rounds down the new tube, things are much, much better. First time out with it I had some generic loads with 162amax, 175smk and 180smk, all loaded at 2.950" COAL. I was disappointed after my first 5 shots through with the amax's, because they shot ~3moa. Gave the bore a quickie cleanup, found nearly zero copper, and fired 3 more rounds with the amax before giving up on them...the start of another 3moa group.

The 175s and 180s however, all did no worse than just over 1/2 moa @ 200 yards. I've now worked up a load using:

175smk
54.8gr H4831sc
2.950" COAL
~2850-2875fps

This load is just *slightly* compressed (I'm using a Forster blue ribbon drop tube though!!), and seems to indicate absolutley zero signs of high pressure. I worked up to 56.6gr in .3gr increments and believe there is a node at about 55.8 or 56gr, but primers were starting to crater pretty good (NO stiff bolt lift or ejector marks) at 56.6gr. I see no reason to push, as the 54.8gr load seems to go about 2850+ out of the 29" Krieger. That velocity number is based on a rock solid 200 yard zero, the Litz G1BC of .64, and my actual drop at 600 yards. Honestly, with a BC that high, you just can't figure the MV to better than +/- 30-40fps at only 600 yards. My exact calculation actually comes out to 2895fps, but I don't believe I'm actually getting that. I'll run it over the chrono soon to find out though.

Unlike before, this load consistently shoots great. Last wednesday I was left with a 5/8" hole in the paper after about 10 rounds at 200 yards. Back at 600 yards, I put 4 shots into 1.5" until my buddy in the pits radioed to tell me, and so of course, I dropped the 5th shot out by 2". Still just over 1/2moa, even so.

Closing thoughts for now:

I'm wondering how my short action is giving up case capacity to a long action? Sure, my bullet is seated deeply @ 2.950" COAL, but I'm still able to comfortably fit (with slight compression of powder charge after filling case with an 8" drop tube) ~55gr H4831sc. The long action folks are running pretty much the same charges with the 175-180 class bullets. So it seems that even though they have more case capacity, they aren't using it...? The velocity I seem to be getting (considering barrel length) seems to be right in line with the 284Win load map in the accurate shooter 7mm cartridge guide...
 
Re: FN SPR 284 Win Build Complete (pretty much)

Update:

Cut the barrel back to 28.25" and added a Badger thruster brake. Recoil wasn't bad, but spotting hits closer than 400-500 yards was tough.

I backed the charge off to 54gr even because it shoots great there, and there's just no reason to lean on it for ranges inside 1250 yards or so.

The JBM dopecard I made for various DAs based on 2825fps with the library Litz data for 175smk is spot on to at least 1220. I made a FRH at 1220 at ASC, while my partner's 308 gave "no calls".... :)

Anyway, gave it a paint job, and will see how she does at the TVP match next weekend.

1348021653_zpsdea89d54.jpg
 
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