Range Report New 6.5mm bullet options: Precision Ballistics! My field experiences

[jbailey]

Guys,
Hello, I'm a 6.5mm shooter. Like many of you, I'm always looking at bullets and the different options available in the market place. I admit it: I find this analysis fun, in a geeky kind of way.

Anyway, some of you may remember the analysis I did on the 6.5mm 130gr JLK bullet from Swampworks, discussed in this thread: http://www.snipershide.com/shooting...9-130gr-jlk-numbers-evaluate-my-analysis.html

I continue to love the 130gr weight class in 6.5mm for its nice compromise of high BC, high muzzle velocity, low recoil and long range splash. My buddies and I have shot these JLKs at a host of matches, including ASC (targets out ~1300yds), with many top 10 finishes. We have also had them out in WY at close to 1 mile and we still see good vapor/splash. Precision has been excellent and easy to find. In short, a great all around choice.

The supply issues at Swampworks have been challenging as have the price increases. So I went looking for another 130gr choice (I know Berger makes one, but I'm a geek and like exploring). This post reports on my efforts here; continue reading if you have an interest.

Surfing the internet bought me to the following site: Precision Ballistics LLC Home (I will abbreviate as PB). I emailed PB's bulletsmith, Don Lahr, and got an immediate email back from him, highlighting all the interesting stuff he is doing with his bullets. His passion is clear. He goes the extra mile on these bullets. His roots are in 100yd benchrest, where 0.01" on group size is everything. It was clear to me that Don's bullets are likely to shoot 100yd groups straw-house-on-fire good. So I ordered pieces to test.

See the attached picture highlighting his bullet on the right, next to a JLK on the left. The PB's are a tangent ogive profile, significantly different from the JLK and from the Berger, which have secant profiles in the 0.6 R/Rt range. The ogive radius length is 15 calibers, which is very long. I'm aware of only one other tangent ogive bullet with an ogive that long, Berger's 140gr LRHPBT. Most tangent bullets are in the 10 caliber range (including most SMKs). PB's also have a very slight rebate on the boat tail (you can barely see it); the boat tail itself is 10*, for 0.20". The meplat has been tightened up to ~0.02" with a pointing die (the picture highlights this pointed meplat nicely; note how small it is compared to the JLK, which itself has a tight meplat of ~0.05"). Overall length is 1.375". Don uses only the outstanding J4 jackets from Berger, same as JLK. He seats, swages and points these bullets on top of the line precision equipment, including Detsch dies, regarded as the best forming dies available.

Looking at these factors as a whole, we have a bullet that offers excellent long ogive led by a tight meplat. The boat tail is standard, with a slight rebate that may or may not improve precision due to reduce dispersion at the muzzle from gas inconsistencies shot to shot. The ogive is strongly tangent, so we are increasing its drag by maybe 5% or so vs the secant JLK and Berger. The tangent profile might make it less seating depth sensitive (see discussion there below). All in, and using Litz regression model to estimate G7 form factor, I think we are in the 0.94-0.95 range, i.e. very good, approaching excellent. At 6.5mm and 130gr, we get a sectional density of 0.266 lb/in^2, which leds us to a G7 BC of 0.28-0.29, roughly 0.56 on the G1 BC scale.

Measuring and weighting the PB bullets up gives us some idea on the precision potential. Not surprisingly, the bullets are outstandingly consistent. Whether I measured or weighted them, I got the same number time and time again. I got ~129.9 gr on my Chargemaster scale for 25 bullets in a row, until I got one that was 130.0gr! Wow! Don goes the extra mile.

Ok, moving off the reloading bench and into the field. I basically did zero load development. I used the exact same load as my go-to 130gr JLK load: 41.7gr of H4350, 2.750" OAL, a CCI BR4 primer (this is a 6.5x47L cartridge). First time out and the bullet was shooting in the 0.1"s at 100yds in my 26" Hart 8 twist barrel. Rounds I thought I pulled went out 0.2"! These things are crazy precise at 100yd.

I swapped out the barrel for my 21" tube. Initially, and for some unknown reason, I loaded these rounds to 2.85" OAL. With this load in the 21" Kreiger 9 twist, I got not so hot results at 100yds: it was going into 0.5" groups and I was getting weird marks on the brass. Checking the load a bit, I noticed that at 2.85" the bullet was jamming into the lands and I was getting marks on brass related to forcing the bullet into these lands. So I moved it back to 2.75" OAL and also loaded up a 2.70" lot and bang, the load went back to shooting in the 0.1"'s! Damn, zero load development and the PBs are drilling absolute bug-holes.

Next, I moved out to 310yds (longest lane I could get on a piece of private land). See attached groups for both the 2.75" and the 2.70" OAL. Each group is 7 rounds (and looks like there was about 3mph of 9 oclock wind as I had 0.2mil on the scope and its roughly 0.1mil off the POA). I estimate the 2.75" lot is doing 2800fps at the muzzle and the 2.70" is hotter and maybe 50fps faster. Group measures about 1" vertically and horizonally, with both lots have multiple bullets go into the same hole. I'm pretty happy given the results and the amount of effort (basically two trips to the range and a few hours on the reloading bench).

Based on these results, I ordered a big fat lot of these bullets and they will be go-to load going forward.

I am going to continue to test these, especially at longer-range. Will hammer out the BC more, but pretty confident 0.55-0.56 BC will have me on steel out a good long ways.

 

[T J]

Thank you for the write up, I hadn't even heard of PB until today. Looks like they are a dern consistent bullet, gotta like that.

What is the turn around from order to shipment?


t

 

[jbailey]

Thank you for the write up, I hadn't even heard of PB until today. Looks like they are a dern consistent bullet, gotta like that.

What is the turn around from order to shipment?


t

I had briefly read about his 6mm benchrest bullets, but didn't know about this 6.5mm bullets until recently. The 6.5mm bullet line is just out in 2013 and they are not well known in the community yet.

Don had my initial 200 piece test order to me in about a week. The second, larger order had to wait on J4 jackets, but Don has those now and is moving product again. Best thing on the turn-around is to email him.

 

[bohem]

Oddly, I am having trouble responding... Let's see if this works.

 

[bohem]

OK, now let's try again...

I'm concerned primarily about the short range test with a lack of MV data. 300yd is a pretty short ToF to quantify the BC here, and without very accurate MV data it's even more difficult.

I simulated the flight with JBM and came up with a BC ranging from 0.555 to 0.795 by keeping the MV's consistent with the estimates just to provide bounds for the estimates. I know James is aware of this issue, and at some point we should get together and setup my hardware at NHRPC to do a little measuring of the BC's.

I don't know why but my initial detailed response isn't be accepted by the forum so perhaps James will comment more completely as I've sent him an email.

Overall, this is encouraging work, well laid out and I know that he is certainly capable of the attention to detail to make the test repeatable and reliable.

 

[jbailey]

Josh's orginial question that was deleted but emailed to me:

Nice write-up James, well done.

Do you have any chronograph data for you to correlate the BC's from? If I read correctly, you said you're estimating the velocities and that's how you drew the BC conclusion.

A 50fps difference in velocity measured only to 300yd for a bullet in this class will calculate to a HUGE difference in actual BC.

2850fps at 0.555 G1, zero'd at 100yd, total drop value (not corrected for zero distance) is 24.0" predicted drop
2800fps at 0.555 G1, zero'd at 100yd, total drop value (not corrected for zero distance) is 24.9" predicted drop

To get that value to match out between them without upping the 2800fps value the G1 value must be pushed up from 0.555 to a whopping 0.795, which I think we can all agree would be unrealistic.

2800fps at 0.795 G1, zero'd at 100yd, total drop value (not corrected for zero distance) is 24.0" predicted drop

I don't mean to be discouraging, this is good work, but you really need to know the MV's for each shot and have a high confidence in that MV value. It is a GIGO issue with the GI being the MV that's estimated. The good news is that they appear to shoot really well and I can't imagine the BC will be "low" on them from the shape.

----James' reply:
I'm not using the 310yd target as proof that the BC is 0.55-0.56; way too short a ToF to produce a number free of error. Instead, my estimated BC comes primarily from two factors: (1) using the Litz regression equation in his Applied Ballistics (where the user inputs the various measurements of the projectiles shapes) and (2) a comparative analysis of other 130gr bullets with known BCs, i.e. the JLKs I have used, the Bergers, and the Normas. For comparision, I estimate that the PB's tangent ogives cost it 5% hit to its form factor relative to those other three, and then it makes back 2-3% of that hit with the closed meplat.

No way is this error free, nor a number that I'm saying is "rock solid." It is just an educated guess.

Also, the source on my MV estimates is my Magneto chrono. All shooting was done with that sucker recording data. Its a good tool, but not without error.

On the offer to come up and test the BC at New Holland, that sounds like a great idea. Will contact you privately on that. Thanks!

 

[peaceatwar]

Jbailey,

Great Intel. Are these bullets going to favor being jammed like other VLD designs? Will you have to chase the lands throughout the wear of barrel. What are you experiences on this with the JLK?

 

[jbailey]

Jbailey,

Great Intel. Are these bullets going to favor being jammed like other VLD designs? Will you have to chase the lands throughout the wear of barrel. What are you experiences on this with the JLK?

Negative. Jamming the PBs resulted in the groups opening up, plus worked the brass. So no plans on jamming. Will not chase the lands either. The 2.70" OAL group shot as good as the 2.75" group, so they clearly don't have much problem with handling bigger jumps.

On the JLKs jumping... we jump all our JLKs, but my buddy's 260 is starting to show a sharp drop in precision as the JLKs jump a lot in his chamber. As such, I think the JLKs don't handle big jumps that well. Hopefully the PBs will continue to handle the jump as it gets bigger.

 

[peaceatwar]

Negative. Jamming the PBs resulted in the groups opening up, plus worked the brass. So no plans on jamming. Will not chase the lands either. The 2.70" OAL group shot as good as the 2.75" group, so they clearly don't have much problem with handling bigger jumps.

On the JLKs jumping... we jump all our JLKs, but my buddy's 260 is starting to show a sharp drop in precision as the JLKs jump a lot in his chamber. As such, I think the JLKs don't handle big jumps that well. Hopefully the PBs will continue to handle the jump as it gets bigger.

You've caught my attention for my creedmoor as I was planning on using 140 Hybrids but with my positive experience with 155 Scenars over a heavier bullet in .308 I am open to the idea of lighter/faster/comparable BC. May get slightly more wind drift but the flatter trajectory is nothing to be written off easily.

Your velocities seem low for a 6.5 though, is that traditional with 6.5x47? I'm expecting 2800-2850 with a 140 Hybrid in a 25" Barrel so a 26" with a 130 running 2800 seems slow. Will likely pick up a box myself and see what the results are. Won't be able to give as accurate readings as the guys here but I can surely report back the drop from my gun with my load chronoed right before that shot from 100-1000(or other laser verified distance) at Lewistown(Mifflin County Sportsmen Club)

Would that give a better idea to BC? I trust my magnetospeed to give accurate readings.

 

[jbailey]

Your velocities seem low for a 6.5 though, is that traditional with 6.5x47? I'm expecting 2800-2850 with a 140 Hybrid in a 25" Barrel so a 26" with a 130 running 2800 seems slow. Will likely pick up a box myself and see what the results are. Won't be able to give as accurate readings as the guys here but I can surely report back the drop from my gun with my load chronoed right before that shot from 100-1000(or other laser verified distance) at Lewistown(Mifflin County Sportsmen Club)

Would that give a better idea to BC? I trust my magnetospeed to give accurate readings.

Peaceatwar (someday you have got to tell me what that means) -

The 2800fps was from my 21" barrel 6.5x47L. The 26" barrel 6.5x47L with the same charge was throwing the 130gr PBs at a touch over 2900fps (it throws the JLKs at 2925). So I lost roughly 100fps going from 26" to 21", approximately 25fps/in, which makes sense to me and to Quickload.

Yes, the chronoed load with a 1000yd drop would certainly help calculate the BC. I agree that the Magneto gives accurate readings. I hope to update this thread in the future with more data from the PBs.

 

[phxfa]

any idea on what these cost?

 

[jbailey]

any idea on what these cost?

Yes sir, they are something like $0.48/piece + s/h. Not as bad as the JLKs but not cheap.

Unfortunately, I only shoot 1k rounds a year of all types of rifle bullets, so my bullet costs are not a big factor relative to other expense (I'm married with 3 kids).

 

[scwoody]

Looks like $51.00 per 100 on the site.

 

[Pusher591]

Just curious and maybe I overlooked it, if I did I apologize but what is the benefit of these vs. the regular Berger 130 VLD's? I know it gives shooters another choice in projectile but at the cost it doesn't seem worth it to me. If these are already pointed as well, doesn't seem like there's room for improvement but you can still point the 130 VLD's and end up with a BC between .57-.58 (assuming you have a minor 3-4% in pointing the VLD's)

 

[jonthomps]

Berger's are the gold standard but it's good to have options! I'd be real interested to see what these are doing in a 6.5 SAUM. I looked on their site but couldn't find any numbers on BC's. Anyone know of any - especially on the 136 and 142's?

 

[jbailey]

Just curious and maybe I overlooked it, if I did I apologize but what is the benefit of these vs. the regular Berger 130 VLD's? I know it gives shooters another choice in projectile but at the cost it doesn't seem worth it to me. If these are already pointed as well, doesn't seem like there's room for improvement but you can still point the 130 VLD's and end up with a BC between .57-.58 (assuming you have a minor 3-4% in pointing the VLD's)

Pusher591-
good question. I think the potential benefit of the PBs over the Bergers (and by extension the JLKs) is the fact that the PB are tangent ogive vs. the secant ogive on the VLDs. This potentially makes them less sensitive to seating depth, and by extension, to erosion of the lands. Some guys will only shoot SMKs because they are all tangent bullets, to take advantage of this. My buddy, the guy with a well-worn 260, has shot out his lands pretty good, and he is getting nasty flyers every 5-7 rounds with the VLD JLKs, flyers that he has no idea where they will go, off 1moa or so. The tangent ogive reduces this, to some unknown amount. In very limited testing, the 130gr PBs didn't produce any flyers in his gun.

There might also be some benefit to the slight rebate in the boat tail in improving precision by reducing impact of imperfections in crown of the barrel. Some benchrest guys swear by it. I just don't know enough to say for sure if this has any impact.

Finally, I have measured and weighed the Bergers and they are not as tight tolerance as the PBs. Again, this sure has impact on benchrest guys, but not sure if the tactical shooter will benefit that much.

The downside of the PBs is the fact that a tangent ogive bullet can never be as low drag as a secant bullet, holding everything else equal. As you cite, point the Berger and its BC is 3-5% better. But if you don't want to spend your time pointing bullets, I think the pointed PB carries about an equal BC as the unpointed Berger...

I guess, summing it up, think of the Precision Ballistics 6.5mm bullets as optimized (in all regards) SMKs.

 

[jbailey]

Berger's are the gold standard but it's good to have options! I'd be real interested to see what these are doing in a 6.5 SAUM. I looked on their site but couldn't find any numbers on BC's. Anyone know of any - especially on the 136 and 142's?

Negative sir, I do not have any experience with the 136's and the 142's, and by extension, have any info on the BCs.

I do believe however that I can offer an educated guess because the 136 and 142 share the exact same exterior as the 130 (them are all formed on the same die, the only differences is the weight of the lead core):

If my G7 form factor of 0.95 is near correct, then the 136gr has a G7 BC of .29, and G1 BC of 0.58. And the 142 has a G7 BC of 0.31 and G1 of 0.61. THESE ARE EDUCATED GUESS HOWEVER!!

 

[Pusher591]

Pusher591-
good question. I think the potential benefit of the PBs over the Bergers (and by extension the JLKs) is the fact that the PB are tangent ogive vs. the secant ogive on the VLDs. This potentially makes them less sensitive to seating depth, and by extension, to erosion of the lands. Some guys will only shoot SMKs because they are all tangent bullets, to take advantage of this. My buddy, the guy with a well-worn 260, has shot out his lands pretty good, and he is getting nasty flyers every 5-7 rounds with the VLD JLKs, flyers that he has no idea where they will go, off 1moa or so. The tangent ogive reduces this, to some unknown amount. In very limited testing, the 130gr PBs didn't produce any flyers in his gun.

There might also be some benefit to the slight rebate in the boat tail in improving precision by reducing impact of imperfections in crown of the barrel. Some benchrest guys swear by it. I just don't know enough to say for sure if this has any impact.

Finally, I have measured and weighed the Bergers and they are not as tight tolerance as the PBs. Again, this sure has impact on benchrest guys, but not sure if the tactical shooter will benefit that much.

The downside of the PBs is the fact that a tangent ogive bullet can never be as low drag as a secant bullet, holding everything else equal. As you cite, point the Berger and its BC is 3-5% better. But if you don't want to spend your time pointing bullets, I think the pointed PB carries about an equal BC as the unpointed Berger...

I guess, summing it up, think of the Precision Ballistics 6.5mm bullets as optimized (in all regards) SMKs.

Thanks Bailey. I didn't think about the Ogive factor. Good stuff and thanks for the reply.

 

[GlockBlock]

Slightly off topic but Nosler recently announced their own 6.5 chambering called the 26 Nosler. So I'd expect more 6.5 mm bullet options a la Nosler.

 

[bohem]

I hope they revamp their 140 Custom Comp bullet. It's a ballistic dog, even if they took their 123 and shoved another 17gr of lead in the core the BC would be higher.