Stuck at low velo for .308

nik f. · July 16, 2013, 01:14 PM

I am new to this forum and while I see a lot of really great info out here I haven't seen anyone address the issue I have been having with my .308 so here goes:

Last fall I bought a used Remington 700 varmint in .308 1-12". The previous owner upgraded the stock to an HS Precision PSV002. I have since added a Timney trigger set to 1.5lbs and a Millet TRS-1 set in Leupold rings.

This is my first centerfire rifle and I am blown away with how accurate it can be at 100-200yds using my reference handload of 38.1gr Varget behind a 175 Sierra MK in Lapua brass using pretty much any primer. (best day out so far was five shots 3/8" c2c)

This load gets me sub MOA all the time but it is pretty slow and I suspect that is the cause of my groups opening up once I get out past 200 yds. I have tried different powders and bullet weights but any time I try to push the velocity past 2400fps, accuracy drops way off. I am a paper hunter so I don't have any specific need for higher velocity for short range but I have access to a range out to 500yds that I would like to play around with and I think I am being limited by my accuracy fall-off.

So my question: Do need to just accept that my rifle will only shoot well with low velo loads or are there directions I can go with my load development/other things I can try? (BTW accuracy with factory ammo is also terrible!)

.22lr · July 16, 2013, 01:31 PM

Hodgdon.com 's reloading data center lists the *starting* charge as several grains higher than your load.

which manual did you base your load off of?

nik f. · July 16, 2013, 01:44 PM

Sierra's. See attached screenshot. Their starting load is 36.3 @ 2200fps.

.22lr · July 16, 2013, 01:50 PM

Huh... Sierra's max load is lower than Hodgdon's starting load.

Both use the 175gr MK HPBT. I have seen this in other manuals, but nothing this drastic.

Its almost the same story for IMR4895.

Ineteresting.

nik f. · July 16, 2013, 01:55 PM

The guy I bought it from stated his developed load was 168 SMK, 45gr Varget but when I tried that I got some head damage from the ejector and backed right off that load.

.22lr · July 16, 2013, 01:56 PM

Not that I don't believe the OP, but 6mmBR has posted Sierra's .308 win load data and the OP is spot on.

Huh. I have seen variation between load manuals, but never a case where the data didn't at least overlap.

.22lr · July 16, 2013, 02:02 PM

Per Serria's Load Data 45gr is over the max charge of Varget.

And yet Hodgdon lists the 168gr MK BTHP with starting charge of 42 and a max charge of 46.

Are you seating your bullets into the lands?

nik f. · July 16, 2013, 02:11 PM

I measured the chamber using the 175 SMK and got something around 2.94in. Apparently Remington's chamber is "lawyered up" according to some posts I've seen. So instead of running the risk of leaving too little bullet in the neck of the case I have gone with the recommended OAL of 2.80in.

reynolds357 · July 16, 2013, 03:26 PM

I dont think Remington's chamber is "lawyered up." I think Remington realizes that those shooting .308 are shooting heavier bullets now than they did 20 years ago.

nik f. · July 16, 2013, 03:38 PM

Might be. In any case I wasn't so sure of the safety of seating a bullet more than .10" longer than recommended.

oneoldsap · July 16, 2013, 03:51 PM

I'd be real concerned about a 1-12 twist stabilizing a 175 Gr. bullet . I've always thought of 1-12 as a Palma twist , 155 Gr. bullets , or lighter . Your rifle seems to be doing okay at low velocity , out to 200 yards . When you add the velocity required for long range , with the heavy bullet , I think you are going to find your rifle , wanting !

allaroundhunter · July 16, 2013, 03:51 PM

The problem with Sierra's manual is that it listed safe charges for the 175 gr mk with those of heavier bullets. Sierra's "max charge" for that load is certainly not the max safe charge.

You need to add several grains if you want better velocity. You will find an accuracy sweet spot as you go higher as well. And yes, seat it deeper.

nik f. · July 16, 2013, 03:57 PM

@oneoldsap: I did too once I researched. I tried 168s (terrible), 155s (okay except for Palmas), and 150s (also okay) but the best accuracy I got was with the heavier 175s and 178s (A-max). It is a varmint barrel after all, so maybe down to the ultra-lights? 135s and 110s?

@allaroundhunter: deeper into the case or deeper into the lands?

allaroundhunter · July 16, 2013, 04:24 PM

Quote:

Originally Posted by nik f.

@oneoldsap: I did too once I researched. I tried 168s (terrible), 155s (okay except for Palmas), and 150s (also okay) but the best accuracy I got was with the heavier 175s and 178s (A-max). It is a varmint barrel after all, so maybe down to the ultra-lights? 135s and 110s?

@allaroundhunter: deeper into the case or deeper into the lands?

Deeper into the lands. The Sierra's like to be set closer into the lands in my experience.

nik f. · July 16, 2013, 04:27 PM

Thanks, I can try that. Anyone have a rule as to minimum bearing surface in the neck of a case?

PawPaw · July 16, 2013, 04:46 PM

Quote:

Originally Posted by reynolds357

I dont think Remington's chamber is "lawyered up." I think Remington realizes that those shooting .308 are shooting heavier bullets now than they did 20 years ago.

No experience with the OP's rifle, but I have a Remington 700 I picked up a couple of years ago that has the longest leade known to modern man. It's so long that if I try to seat a 150 grain flat-based bullet into the lands, the base of the bullet isn't even in the case. My particular rifle has a 1983 date code, and I got it at a pawn shop. Looking at the rifling, it looks to have been shot very little. Probably someone's grandpas rifle that stayed in a closet for 30 years, the old man died and his non-shooting grandkids took it to the pawn shop. The barrel is 1:10, and it shoots 168s fairly well, but there's no question about seating the bullet out to the lands. It ain't happening. That bullet is going to jump and we just have to work with that.

TATER · July 16, 2013, 04:51 PM

Nik f, Remington 700s are too generous, You will run out of magazine first.. I would load to max functioning magazine length.
The load that you stated 45gr Varget and a 168SMK is a common load with Winchester Brass, and very well could show pressure with your lapua brass..
I would make sure that my scales are level and calibrated.. Start 42.0 grs with the 168s and work up until you start to see pressure. This needs to be taken
To the reloading forum at this point.. But, You can do better than 2400fps even with a 20' barrel.

stubbicatt · July 16, 2013, 04:53 PM

Quote:

Thanks, I can try that. Anyone have a rule as to minimum bearing surface in the neck of a case? Says Nik F.

I have read that one should have at least the diameter of the bullet stuffed in the case. Thus if bullet is .308" diameter, one should have at least 1/3" of bullet shank in the case. Whether that is bearing surface only, or whether that includes the boat tail, I don't know...

James K · July 16, 2013, 07:33 PM

Loading manuals are keyed toward safety and velocity, not accuracy; there are just too many variables. I agree that the 1 in 12 twist is not a good choice for general use in a .308 for the reasons mentioned.

Jim

Jimro · July 17, 2013, 03:19 AM

1:12 is fine.

Sierra publishes data they get.

Hodgdon publishes data they get.

Now try to figure out Federal Gold Medal Match or Black Hills Match, a 175 SMK at over 2500 fps. They aren't useing Sierra's data.

Get a box of Fed GMM. If it shoots tight in your rifle, then you can clearly up the velocity a bit.

Jimro

4runnerman · July 17, 2013, 06:04 AM

try RL-15 ( If you can find any ). start with about 39 gns and work up from there.
Also try CCI-BR primers, 2.80 for length is good. My pet 308 load is 43.2 RL-15 and 175 smk,s. Seems like all 308's love RL-15.

Bart B. · July 17, 2013, 07:30 AM

Note the fact that the 7.62 NATO round was developed around a 1:12 twist barrel as that twist for the 2800 fps muzzle velocity of the 150-gr. (or thereabouts) spun it at the ideal rpm rate for optimum stabilization.

Even Harry Pope, the famous barrel maker knew back in the early 1900's that the new 172-gr. machine gun bullet shot most accurate from a .30-06 with a 1:12 twist and he made barrels for the US Palma Team that way. Back then, the velocity of that bullet in the .30-06 was about what it is today from the M118 match round.

And the 172-gr match bullets from the M118 7.62 match ammo also stabilized quite well from the M14's 1:12 twist. So did Sierra 180 and 190 HPMK's from both the 22 inch M14 barrels and 24 inch M1 barrels with handloaded 7.62 NATO ammo. Many a match was won and records set with such stuff.

Winchester's first Model 70's in .308 Win. had 1:12 twist barrels. Their 200-gr. hunting bullets stabilized well in that twist. Many a 200-gr. Western match bullet was shot in their 1:12 twist match barrels very accurate through 1000 yards.

nik f. · July 17, 2013, 09:05 AM

Wow, thanks for all the info!

I don't think I mentioned it originally but my barrel is the 26" medium weight varmint model. According to Remington it was produced in 2010.

At the risk of making this a reloading thread: RL-15 is something that I always look for when I get to Cabela's or any other supplier but so far I haven't had any luck. I have tried BR2 primers (800 rounds so far) but get pretty identical results with WLR and CCI 200 at half the price and better availability.

I just found some GMM 175s at Midway's site so I ordered a box. Hopefully I will get them before my weekly trip to the range.

As far as the stabilization of the heavier bullets goes, I have never seen an oblong hole in any target I have shot out to 300yds.

Jimro · July 17, 2013, 10:05 AM

You have Varget, I'd start there.

Appropriate powders for maximum accuracy are: Varget, H4895, IMR4064, Reloader15. As far as I can tell they are temp stable in that order as well, with Re15 the least temp stable.

Jimro

nik f. · July 17, 2013, 10:11 AM

Start with Varget and play with OAL? As this is a range gun I never use the magazine so I am not worried about the rounds fitting. I can start seating the bullets farther out as their lengths allow. I have heard that seating into the lands can cause pressure spikes. Has anyone seen evidence of that?

July 16, 2013, 01:14 PM	#1
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	Stuck at low velo for .308 I am new to this forum and while I see a lot of really great info out here I haven't seen anyone address the issue I have been having with my .308 so here goes: Last fall I bought a used Remington 700 varmint in .308 1-12". The previous owner upgraded the stock to an HS Precision PSV002. I have since added a Timney trigger set to 1.5lbs and a Millet TRS-1 set in Leupold rings. This is my first centerfire rifle and I am blown away with how accurate it can be at 100-200yds using my reference handload of 38.1gr Varget behind a 175 Sierra MK in Lapua brass using pretty much any primer. (best day out so far was five shots 3/8" c2c) This load gets me sub MOA all the time but it is pretty slow and I suspect that is the cause of my groups opening up once I get out past 200 yds. I have tried different powders and bullet weights but any time I try to push the velocity past 2400fps, accuracy drops way off. I am a paper hunter so I don't have any specific need for higher velocity for short range but I have access to a range out to 500yds that I would like to play around with and I think I am being limited by my accuracy fall-off. So my question: Do need to just accept that my rifle will only shoot well with low velo loads or are there directions I can go with my load development/other things I can try? (BTW accuracy with factory ammo is also terrible!)

July 16, 2013, 03:51 PM	#11
oneoldsap Senior Member Join Date: September 16, 2009 Location: I live in the foot of the Green Mountains of Vermont Posts: 1,602	More Twist I'd be real concerned about a 1-12 twist stabilizing a 175 Gr. bullet . I've always thought of 1-12 as a Palma twist , 155 Gr. bullets , or lighter . Your rifle seems to be doing okay at low velocity , out to 200 yards . When you add the velocity required for long range , with the heavy bullet , I think you are going to find your rifle , wanting ! __________________ Don't forget to have your liberals spayed or neutered !

July 16, 2013, 03:51 PM	#12
allaroundhunter Senior Member Join Date: May 6, 2012 Location: Southeast Texas Posts: 1,670	Re: Stuck at low velo for .308 The problem with Sierra's manual is that it listed safe charges for the 175 gr mk with those of heavier bullets. Sierra's "max charge" for that load is certainly not the max safe charge. You need to add several grains if you want better velocity. You will find an accuracy sweet spot as you go higher as well. And yes, seat it deeper.

July 17, 2013, 03:19 AM	#20
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	1:12 is fine. Sierra publishes data they get. Hodgdon publishes data they get. Now try to figure out Federal Gold Medal Match or Black Hills Match, a 175 SMK at over 2500 fps. They aren't useing Sierra's data. Get a box of Fed GMM. If it shoots tight in your rifle, then you can clearly up the velocity a bit. Jimro __________________ Machine guns are awesome until you have to carry one.

July 17, 2013, 06:04 AM	#21
4runnerman Senior Member Join Date: January 16, 2010 Location: Minnesota Posts: 3,577	try RL-15 ( If you can find any ). start with about 39 gns and work up from there. Also try CCI-BR primers, 2.80 for length is good. My pet 308 load is 43.2 RL-15 and 175 smk,s. Seems like all 308's love RL-15. __________________ NRA Certified RSO NwCP- Performance Isn't Optional

July 16, 2013, 01:31 PM	#2
.22lr Senior Member Join Date: July 14, 2007 Posts: 245	Hodgdon.com 's reloading data center lists the starting charge as several grains higher than your load. which manual did you base your load off of?

July 16, 2013, 01:50 PM	#4
.22lr Senior Member Join Date: July 14, 2007 Posts: 245	Huh... Sierra's max load is lower than Hodgdon's starting load. Both use the 175gr MK HPBT. I have seen this in other manuals, but nothing this drastic. Its almost the same story for IMR4895. Ineteresting.

July 16, 2013, 01:55 PM	#5
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	The guy I bought it from stated his developed load was 168 SMK, 45gr Varget but when I tried that I got some head damage from the ejector and backed right off that load.

July 16, 2013, 01:56 PM	#6
.22lr Senior Member Join Date: July 14, 2007 Posts: 245	Not that I don't believe the OP, but 6mmBR has posted Sierra's .308 win load data and the OP is spot on. Huh. I have seen variation between load manuals, but never a case where the data didn't at least overlap.

July 16, 2013, 02:02 PM	#7
.22lr Senior Member Join Date: July 14, 2007 Posts: 245	Per Serria's Load Data 45gr is over the max charge of Varget. And yet Hodgdon lists the 168gr MK BTHP with starting charge of 42 and a max charge of 46. Are you seating your bullets into the lands?

July 16, 2013, 02:11 PM	#8
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	I measured the chamber using the 175 SMK and got something around 2.94in. Apparently Remington's chamber is "lawyered up" according to some posts I've seen. So instead of running the risk of leaving too little bullet in the neck of the case I have gone with the recommended OAL of 2.80in.

July 16, 2013, 03:26 PM	#9
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,165	I dont think Remington's chamber is "lawyered up." I think Remington realizes that those shooting .308 are shooting heavier bullets now than they did 20 years ago.

July 16, 2013, 03:38 PM	#10
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	Might be. In any case I wasn't so sure of the safety of seating a bullet more than .10" longer than recommended.

July 16, 2013, 03:57 PM	#13
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	@oneoldsap: I did too once I researched. I tried 168s (terrible), 155s (okay except for Palmas), and 150s (also okay) but the best accuracy I got was with the heavier 175s and 178s (A-max). It is a varmint barrel after all, so maybe down to the ultra-lights? 135s and 110s? @allaroundhunter: deeper into the case or deeper into the lands?

July 16, 2013, 04:27 PM	#15
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	Thanks, I can try that. Anyone have a rule as to minimum bearing surface in the neck of a case?

July 16, 2013, 04:51 PM	#17
TATER Senior Member Join Date: November 19, 2002 Location: Mississippi Posts: 963	Nik f, Remington 700s are too generous, You will run out of magazine first.. I would load to max functioning magazine length. The load that you stated 45gr Varget and a 168SMK is a common load with Winchester Brass, and very well could show pressure with your lapua brass.. I would make sure that my scales are level and calibrated.. Start 42.0 grs with the 168s and work up until you start to see pressure. This needs to be taken To the reloading forum at this point.. But, You can do better than 2400fps even with a 20' barrel.

July 16, 2013, 07:33 PM	#19
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Loading manuals are keyed toward safety and velocity, not accuracy; there are just too many variables. I agree that the 1 in 12 twist is not a good choice for general use in a .308 for the reasons mentioned. Jim

July 17, 2013, 07:30 AM	#22
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	Note the fact that the 7.62 NATO round was developed around a 1:12 twist barrel as that twist for the 2800 fps muzzle velocity of the 150-gr. (or thereabouts) spun it at the ideal rpm rate for optimum stabilization. Even Harry Pope, the famous barrel maker knew back in the early 1900's that the new 172-gr. machine gun bullet shot most accurate from a .30-06 with a 1:12 twist and he made barrels for the US Palma Team that way. Back then, the velocity of that bullet in the .30-06 was about what it is today from the M118 match round. And the 172-gr match bullets from the M118 7.62 match ammo also stabilized quite well from the M14's 1:12 twist. So did Sierra 180 and 190 HPMK's from both the 22 inch M14 barrels and 24 inch M1 barrels with handloaded 7.62 NATO ammo. Many a match was won and records set with such stuff. Winchester's first Model 70's in .308 Win. had 1:12 twist barrels. Their 200-gr. hunting bullets stabilized well in that twist. Many a 200-gr. Western match bullet was shot in their 1:12 twist match barrels very accurate through 1000 yards.

July 17, 2013, 09:05 AM	#23
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	Wow, thanks for all the info! I don't think I mentioned it originally but my barrel is the 26" medium weight varmint model. According to Remington it was produced in 2010. At the risk of making this a reloading thread: RL-15 is something that I always look for when I get to Cabela's or any other supplier but so far I haven't had any luck. I have tried BR2 primers (800 rounds so far) but get pretty identical results with WLR and CCI 200 at half the price and better availability. I just found some GMM 175s at Midway's site so I ordered a box. Hopefully I will get them before my weekly trip to the range. As far as the stabilization of the heavier bullets goes, I have never seen an oblong hole in any target I have shot out to 300yds.

July 17, 2013, 10:05 AM	#24
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	You have Varget, I'd start there. Appropriate powders for maximum accuracy are: Varget, H4895, IMR4064, Reloader15. As far as I can tell they are temp stable in that order as well, with Re15 the least temp stable. Jimro __________________ Machine guns are awesome until you have to carry one.

July 17, 2013, 10:11 AM	#25
nik f. Member Join Date: July 16, 2013 Location: Suburb of Milwaukee WI Posts: 23	Start with Varget and play with OAL? As this is a range gun I never use the magazine so I am not worried about the rounds fitting. I can start seating the bullets farther out as their lengths allow. I have heard that seating into the lands can cause pressure spikes. Has anyone seen evidence of that?