FNH SPR A5 Bolt Action Rifle - Range Report (More Pics): Chrome-lined Barrel Myth

[semiautosniper]

Pictures can be found here:

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Range Report:

Rifle Specs:
1) FNH SPR A5 rifle with 4 round DBM magazine, McMillan A5 Stock.
2) 20-inch 1/12 twist, 4 grooves, 308 Win, hammer-forged, chrome-lined, mirror polished, chrome-moly, blued, fluted, barrel with match crown.
3) Custom pillar bedding and devcon bedding job done by Calgunner - Kendog4570 (Gunsmith, Aptos, Ca)
4) Installation of Badger Knob by Ken.
5) Factory action, trued at the factory, unaltered.
6) Factory-installed 20 MOA mount base.
7) 3.5-lb factory stock trigger

Scope Specs:
1. Nightforce 5.5 - 22 x 50 NXS, Zero stop, MOA reticle.
2. Nightforce steel rings

Shooting Condition:
1. from bench
2. 100 yards
3. no wind
4. warm barrel shots (4-5 shot series, 20 seconds between shots)
5. Harris bipod and with/without rear sandbag

Result:
1. Center: American Eagle 168 grain OTM, no rear sandbag, 0.95 MOA
2. Left Lower Corner: American Eagle 168 grain OTM, with rear sandbag, 0.53 MOA
3. Right Top Corner: Blackhills Match 168 grain BTHP, rear sandbag, 1.06 MOA
4. Right Lower Corner: Federal Gold Cup 168 grain BTHP, rear sandbag, 0.57 MOA
5. Left Top Corner: Hornady Match 168 grain BTHP, 5 rounds, rear sand bag, 0.42 MOA

Second Range Trip:
1. Bench and Prone with 168 grain Hornady BTHP.
2. 0.43 MOA (4 shots), 0.6 MOA (4 shots), 0.26 MOA (4 shots) - (all bench)
3. 0.59 MOA (5 shots) - (prone)

Conclusion:

A 1/12 twist, 20 inch barrel is probably good up to 700 - 800 yards with 168 grain bullets, not sure about 175 grain given the lower twist rate. FN's Chrome-lined barrel has excellent accuracy, but mine didn't like Blackhills ammo. FN SPR barrels are rated for 15,000 rounds to maintain 0.5 MOA. The Myth that chrome-lined barrel cannot be used as match-grade barrels is outdated; both FN SPR and SAKO TRG use chrome-lined barrels, both with great results achieving sub-MOA. However, these barrels are very different from M14 USGI chrome-lined barrels, FN barrel is mirror-polished whereas M14 barrels are pretty rough on the bore. Kendog4570 from Aptos did an excellent and professional pillar bedding job with turn-around time of only 2 weeks, and I highly recommend him as a licensed gunsmith.

SAS

[MrPlink]

sweet!

but whats the chrome lined barrel myth?

[Quiet]

sweet!

but whats the chrome lined barrel myth?

That chrome lined barrels are not as accurate as non-chrome lined barrels.

[Solidsnake87]

The FN SPR rifles are VERY accurate shooters. Nice rifle!

The "myth" is fact though.

A match grade barrel is made to tight tolerances that are uniform throughout the barrel. Generally this is achieved by lapping all internal surfaces so that they are essentially polished flats (i.e, no burs, jags, or machining pits).

A Chrome lined barrel can be made using the same proceedures as a match grade barrel. However, the potential for the creation of a non-uniform barrel occurs during the chrome lining process because its impossible to control the exact thickness of the chrome lining. Chrome lined barrels are generally machined with a bore that is about .002" oversize to accomodate for the average thickness of the chrome lining.


Chrome lined barrels are definitely capable of great accuracy. its not hard to get an AR to shoot 1" or better groups with a chrome/GI barrel and match ammo.

The process that FN uses to make its SPR barrels is not common to my knowlegde. They machine a match grade barrel and chrome line it. Most chrome lined barrels are standard factory barrels intended for military or rough use, so they would not have the maximum accuracy potential from the outset. FN's process ensures that their chrome lined barrels perform at maximum possible performance in spite of the potential accuracy risks that chrome lining can cause.

Accuracy wise,



Since the majority of chrome lines barrels are meant for military/rough use

[semiautosniper]

I thought FN SPR barrels are made from machine gun blanks...? That's why they claim "machine-gun durability".

[semiautosniper]

more pictures uploaded from my second trip to range.

[bwiese]

The real answer is that a chrome-lined bbl can equal a non-lined barrel, it's just a function of the selection/reject criteria since chroming is a one-time, essentially unfixable process.

FN rejects a higher proportion of bbls on this gun than they would, say, for M16 bbls.

And the lifetime is much higher... which would you rather have, a barrel that starts out fine but changes after 1500-2500 rounds, or one that is consistently good for up to 15000 rounds?

[semiautosniper]

The real answer is that a chrome-lined bbl can equal a non-lined barrel, it's just a function of the selection/reject criteria since chroming is a one-time, essentially unfixable process.

FN rejects a higher proportion of bbls on this gun than they would, say, for M16 bbls.

And the lifetime is much higher... which would you rather have, a barrel that starts out fine but changes after 1500-2500 rounds, or one that is consistently good for up to 15000 rounds?

My sentiment exactly... I have a Robar SR90 but I seldom shoot it since I acquired it, because I didn't want to burn out the throat area since 416 stainless barrels are great for +3500 or so rounds, and then I will have to re-barrel, which will set me back at least + 6 months for turn-around time at Robar. My SPR shoots just as well as my Robar at 100 yards, although I have to test the SPR out in Sacramento some point in the future; although with a 20-inch barrel with 1/12 twist, I may have to handload 155 grain to get the max performance at 1000 yards... But I don't handload... that's the problem... Maybe I will just stick to 500-800 yards. (And again, SPR stands for "Special Police Rifle", and it was designed for engagement within 200 yards when unbedded... So I will be happy if it shoots well up to 600 yards after pillar bedding).

SAS