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1:8 fast enough for hornady 75 gr BTHP?


jaredr

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shot out the barrel of my S&W VTAC carbine, rebarreled with an 18" ranier arms rifle-length gas system, twist is 1:8. Sierra 69gr SMK's are sub-MOA with 24 gr RE15 so the barrel has accuracy potential. Tried 75gr hornady BTHP's (RE15, various charges from 21 - 24 gr) and groups opened up to 2.5". They're not keyholing but definitely not the accuracy I'm looking for. Anyone have any experience trying these in 1:8 twist barrel - wondering if the twist rate is just not sufficient to get the most out the 75 gr bullet.

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thanks, i've read from several others that RE15 is their "go to" powder for heavier bullet loads so wasn't sure if it was a problem with my barrel twist or possible other factors. sounds like I can play around with seating depth a bit but may just have to try some other powders.

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As mentioned above, they will work with that twist rate. I was knocking around a steel plate at 500 with that combo this afternoon. Maybe your barrel needs a different powder or seating depth or other tweak to get em going the way you want. Peter's suggestion about seating as long as you can still have them feed well is prob a great place to start.

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shot out the barrel of my S&W VTAC carbine, rebarreled with an 18" ranier arms rifle-length gas system, twist is 1:8. Sierra 69gr SMK's are sub-MOA with 24 gr RE15 so the barrel has accuracy potential. Tried 75gr hornady BTHP's (RE15, various charges from 21 - 24 gr) and groups opened up to 2.5". They're not keyholing but definitely not the accuracy I'm looking for. Anyone have any experience trying these in 1:8 twist barrel - wondering if the twist rate is just not sufficient to get the most out the 75 gr bullet.

The 75 grain Hornadays have a shorter bearing surface and were actually designed to be one of the few heavies that work in a 1/9 as well. Only way to find out exactly how well they will shoot is to shoot them in your gun. That said the 75 grain Hornadys don't group that well for me and I use Nosler 77's and Sierra 77's. Nosler is the best for the money in that weight class with accuracy nearly as good as the Sierra's at 2/3 the cost.

Pat

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I've always had them shoot very well in umpteen barrels, but some barrels just don't like some bullets for no obvious reason.

Another possibility - are you sure it's really a 1-8" twist? Barrels vary for several reasons but use a cleaning rod and a tight patch to measure the length of rod required for a full rotation. I'm not familiar with Rainier (had to Google 'em) and no one I know has ever mounted one on a match rifle.

Finally, I'll be happy to dispose of those sub-standard awful bullets for you if you need me to. ;)

Mark

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To answer your original post ...

Yes ... a 1:8 barrel will shoot 75 gr. bullets fine. As a matter of fact, I shoot them in all of my ARs whether they are 1:9 or 1:7 ... it makes no difference. The 77s tend to be too long for the 1:9 barrels to stabilize, but the 75s are just the right length.

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appreciate the feedback, looks like I need to either find a different powder or possibly just different bullets. Unfortunately all i have on hand are ball powders (aa2230, SMP735) which I've read are not optimal for heavy bullets. I've got load data so I'll give it a try, otherwise may just need try some sierra's if I want a heavier weight bullet for distance.

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Try some 8208xbr ....

Sent from my PG06100 using Tapatalk 2

X2

2230 is way too dirty! You will find yourself cleaning more often if you use it.

IMR 8208 XBR is an excellent powder, and I use it in everything from .223 to 45-70 Gov't. It isn't temp sensitive like a lot of powders are. 8208XBR is the old 'Thunderbird' T-322 powder that the benchrest shooters in the 70's loved so much. Try it ... you won't be disappointed.

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  • 2 weeks later...

If you're asking about my gun, it's a 20" Wilson Arms (not Wilson Combat) bull barrel on an Armalite chassis.

I only shoot the 75s (whether factory or the handload referenced above), although I once had to shoot the P223E load from Federal (55 gr. GameKing bullet). With all of these, the gun averages 3/4" at 100.

One load I did find that wouldn't work was the 55 gr. Ballistic Tip. My Benelli will shoot better groups at 100 with buckshot....

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  • 3 weeks later...

see what your gourps are at out to 300, 400, and 500 yards. a lot of the longer bullets will not stabalize till they got some flight distance on them. its not so much the weight, but the bearing surface/bore diameter that determines what twist rate a bullet needs. I use to shoot 75gr A-max out of my 1-7.7 twist Krieger AR barrel and it would shoot horrible groups at 100 yard, but would go sub-moa at 600 yards.

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I couldn't get the Hornady 68s or 75s to shoot too well out of either my 18" 1/8 JP or my 20" 1/8 WOA SDM barrel.

However, since the 69gr SMKs turned out to shoot extremely well out of both I didnt spend too much time working with the Hornadys.

Edited by gose
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  • 4 weeks later...

Guy's I just want to add that in my testing for Grouping +-.5gr is the difference between a 3" group and a 1/2" group at 100 yards. Now you can be down a full grain and the target looks like you are shooting buck shot. So you have to develop a load, I do a +.2gr and load 10 at each level and test till I find the one that groups best.

Just my 0.02 everthing could be right but you need a little bit more or less powder to find the sweet spot to get it to group.

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  • 2 weeks later...

I have had good luck with 75 bthp's and Varget. 23.5 gr and 2.250 OAL. Consistently sub-moa (back to back 5-shot groups) in a Nordic 18" barrel. I have also been wanting to try some IMR 8208 XBR but have not had a chance lately. There is no doubt that an extruded stick powder like Varget is kind of a pain to work with in comparison to ball powders.

Regarding stabilization in a 1:9 barrel - I have been meaning to shoot some of these loads in my brother's 1:9 carbine, but haven't had a chance. Will report back when I do.

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  • 3 weeks later...

I've had great luck with Hornady's factory 75g TAP out of every gun I've ever used it with. My WOA/Rainier Arms Ultramatch 18" manages 1/2 MOA with that round.

I couldn't get the Hornady 68s or 75s to shoot too well out of either my 18" 1/8 JP or my 20" 1/8 WOA SDM barrel.

However, since the 69gr SMKs turned out to shoot extremely well out of both I didnt spend too much time working with the Hornadys.

Just goes to show that even the same barrel stock can give different results with the same bullets. 75g Horandy TAP loaded with their BTHP bullet went 1/2 moa for me in my WOA/Rainier Arms Ultramatch 18". I haven't hand loaded for that bullet yet, but when I do, I'll use the factory TAP ammo as my COAL starting point.

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