.30 HRT info? - Page 1

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Posted: 6/11/2006 8:08:26 PM EDT

Could anyone please give more info on the .30 HRT?

I've read what Marty and Randall have on their websites and am interested. I guess I'm mostly interested in real-world velocity comparisons between the .300/221, .30 HRT, and 7.62x39.

I've found quite a bit of load data for the .30 Herrett and don't see that much improvement over the .300 /221. I imagine this is from the lower pressures needed with the .30-30 parent case ... shouldn't the 6.8 parent case make the .30 HRT a much higher pressure round?

Thanks for any info.

Scot

Posted: 6/12/2006 11:18:01 PM EDT

[#1]

I recently emailed Marty about the .30 HRT. He said it is a rimless .30 Herrett, and would use .30 Herrett loading data as well. It sounds like an interesting round. I am considering it, or the 6.8SPC for my next build. The jury is still out as to which one it will be. The Herrett out of a handgun is quite a hotrod. I would guess that an additional 6-8 inches of barrel would really step up the velocity.
Sorry I couldn't offer more info, but I am still in the research stages also.

Posted: 6/13/2006 4:22:49 AM EDT

[#2]

For comparison

300-221
Length case 1.390"
capacity case 24.95 gr water
max pressure (QL) 50700 psi

7.62 x 39
Length case 1.523
capacity case 35.6 gr water
max pressure (QL) 51400 psi

30 HRT
Length case 1.605
capacity case gr water 35.0
max pressure (QL) psi 55000

In a 16" barrel, loaded to 50000 psi, the following predicted results

125 gr Sierra SP, seated 0.25 deep
300-221 estimated 2200-2250 fps - this leaves room in the mag, and offers reasonable neck tension
7.62 x 39 estimated 2400-2450 fps - this is slightly deeper than "factory" loaded
.30 HRT estimated 2450-2550 fps - this is far deeper than the mag requires

168 gr SMK, seated to max COL mag allows, 50000 psi
300-221 estimated 1850-1900 at 2.255 COL
7.62 x 39 estimated 2050-2100 at 2.255 COL
.30 HRT estimated 2050-2100 at 2.280 COL

240 gr SMK, seated to max COL mag allows, 50000 psi
300-221 estimated 1300-1400 at 2.255 COL
7.62 x 39 estimated 1600-1650 at 2.255 COL
.30 HRT estimated 1600-1650 at 2.280 COL

Until recently (before CP) there were no really reliable mags that were readily available for the 7.62 x 39. Also, there have been reports of bolt failures for the 7.62 x 39. The CP mags should fix the mag issue and there are new generation 7.62 x 39 bolts available that should address the bolt issue. With Wolf and others making 7.62 x 39 ammo, it is economical, provided you can find it (people have reported short supplies)

The .30 HRT is essentially the same as the 7.62 x 39 but offer the ability to use .308 bullets (the 7.62 x 39 is really a .311) and match grade .308 barrels. Ballistically they are matched and folks have compared them to the .30-30 which seems reasonable. It uses the 6.8 bolt, brass and mags, which can present a supply or cost issue in some case. CP now also makes 6.8 mags (they are the same body as the 7.62 mags) and starting load data for the .30 HRT can be found in loading manuals. Dies are standard .30 Herrett dies.

We developed the .30 HRT to address the aforementioned issues with the 7.62 x 39 (mags and bolt failures) as well as some of the issues with the .300-221 (more power as well as no need for proprietary gas systems to run subsonic loads, the larger case capacity offers more flexibility)

Is it a "new, improved and much better" cartridge. Nope. Nothing more than those that already exist. It just seeks to fix a few minor issues.

Hope that helps?

Posted: 6/13/2006 1:29:39 PM EDT

[#3]

WOW Marty you really deliver the info!! Thanks!

I have a .300/221 I really like but can't get velocities anywhere near listed without wrecking brass (mostly stretched primer pockets). The pressure in that little case goes up FAST so a bigger case is a definite plus.

Other than mags and a new bolt, could I convert my .300/221 to .30 HRT by simply having the chamber reamed? I have a 16" hbar with the gas port in the carbine location... NOT setup for subsonic .300 loads.

Thanks,

Scot

Posted: 6/13/2006 7:58:15 PM EDT

[#4]

Quoted:

Other than mags and a new bolt, could I convert my .300/221 to .30 HRT by simply having the chamber reamed? I have a 16" hbar with the gas port in the carbine location... NOT setup for subsonic .300 loads.

Thanks,

Scot

That was the other part of the idea, to be able to take existing 300-221 barrels and simply rechamber them ...

Posted: 6/14/2006 8:45:57 AM EDT

[#5]

Cool, how many $s are we talking (I mean, strictly for the chamber reaming)?

Thanks,
Scot

Posted: 6/14/2006 11:36:20 AM EDT

[#6]

Quoted:
Quoted:

Other than mags and a new bolt, could I convert my .300/221 to .30 HRT by simply having the chamber reamed? I have a 16" hbar with the gas port in the carbine location... NOT setup for subsonic .300 loads.

Thanks,

Scot

That was the other part of the idea, to be able to take existing 300-221 barrels and simply rechamber them ...

Not trying to hijack the thread, but your answer puzzles me. I was under the impression that removal of the extension was cost prohibitave in general. Is this not the case, or can you simply ream with the extension in place. This might be helpful to know, next time I find myself at a gunshow that might have "intersting" barrels for sale.

Thanks,

Craig

Posted: 6/16/2006 10:04:38 AM EDT

[#7]

Quoted:
Not trying to hijack the thread, but your answer puzzles me. I was under the impression that removal of the extension was cost prohibitave in general. Is this not the case, or can you simply ream with the extension in place. This might be helpful to know, next time I find myself at a gunshow that might have "intersting" barrels for sale.

Craig-

It's not a problem to ream with the extension in place, you just have to be a little more creative how you measure as you go so you don't ream too deep.
Also, it's not really a big deal to remove and re-install the SAME barrel extension.
It's swapping extensions that's the problem.

I don't know what Marty charges for rechambers, but I am usually right around $75 to $95 depending on the complexity.

Posted: 6/16/2006 6:27:30 PM EDT

[#8]

Thanks for the info Randall,

I have another idea (similar) that I'll e-mail you on your site. It might be too lame and I don't want to sound like any more of a dumbass in public.

Scot

Posted: 6/28/2006 11:06:23 PM EDT

[#9]

I like the idea. I have been kicking around the idea of a 7.62x39 for a while but have had some reservations. Already having one 6.8 and in the middle of building another one so this would be a nice way to keep different cases minimized. Does anyone have any solid ballistic data on this cartridge?

Posted: 6/29/2006 9:14:06 PM EDT

[#10]

I don't have any actual chronograph data, but I can run the quickload predictions for any barrel length and bullet weight you want and post them here.
Just give me a couple pointers on what you want.

Some samples:
20" barrel & 110gr bullet @ 55K psi will get you around 2750fps
16" barrel & 150gr bullet @ 55K psi will get you around 2300fps
20" barrel & 180gr bullet @ 50K psi will get you around 2000fps
16" barrel & 240gr bullet @ 50K psi will get you around 1500fps

Posted: 6/29/2006 9:39:44 PM EDT

[#11]

I appreciate the reply Randall. However I was hoping for chronographed velocities to near max pressures. Power factors I am sorry to say mean nothing to me. Also in my part of the world subsonic suppressed setups are out of the question.

Posted: 6/29/2006 9:44:16 PM EDT

[#12]

Quoted:
I appreciate the reply Randall. However I was hoping for chronographed velocities to near max pressures. Power factors I am sorry to say mean nothing to me.

I was copying and pasting info from some emails I sent and that post slipped out before I edited it to make sense.
Check above again and I think it will make more sense...

Posted: 6/29/2006 10:02:49 PM EDT

[#13]

Looking at 16" barrel using 110-150 gr. bullets. 2400 from a 16" w/150 is pretty respectable. It seems that it could actually outperform the 7.62x39. As I understand it the same loading data for the Herret can be used and I am assuming the same powders or slightly slower burning? Thanks again Randall.

Posted: 6/29/2006 10:15:53 PM EDT

[#14]

Quoted:
Looking at 16" barrel using 110-150 gr. bullets. 2400 from a 16" w/150 is pretty respectable. It seems that it could actually outperform the 7.62x39. As I understand it the same loading data for the Herret can be used and I am assuming the same powders or slightly slower burning? Thanks again Randall.

We can run the pressures higher in the 6.8 case than in the 30-30 parent of the 30 herrett.
Herrett data typically stops at 40K psi while 6.8 cases run to 55K psi.
You can start with Herrett data and work UP from there while watching for pressure signs.
Here is a quickload series for a 150gr bullet to 55K psi max loads:


Cartridge          : .30 HRT
Bullet             : .308, 150, Speer SP 2023
Cartridge O.A.L. L6: 2.275 inch
Barrel Length      : 16.0 inch

Predicted Data for Indicated Charges of the Following Powders.

Matching Maximum Pressure: 55000 psi

or a maximum loading ratio or filling of 105 %

These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

21 loads produced a Loading Ratio below user-defined minimum of 75%. These powders have been skipped.

Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Alliant Reloder-10x                103.7     28.3     1.83    2335    98.6    55000    8213   0.892  !DANGEROUS LOAD
SNPE Vectan SP 10                  105.0     30.6     1.98    2318    93.9    53874    8525   0.892  !DANGEROUS LOAD
Winchester 296                      81.9     23.8     1.54    2303   100.0    55000    7355   0.916  !DANGEROUS LOAD
IMR 4198                           104.5     26.3     1.70    2292    99.3    55000    7505   0.885  !DANGEROUS LOAD
Ramshot X-Terminator               105.0     29.7     1.92    2290    94.7    51953    8330   0.908  !DANGEROUS LOAD
Vihtavuori N120                    102.5     26.4     1.71    2276   100.0    55000    6970   0.897  !DANGEROUS LOAD
Alliant Reloder- 7                  95.9     25.5     1.66    2272   100.0    55000    7142   0.925  !DANGEROUS LOAD
Accurate 2200                       98.1     28.2     1.83    2265    93.3    55000    7839   0.897  !DANGEROUS LOAD
Accurate No.1680                    91.5     26.5     1.72    2261    96.8    55000    7569   0.899  !DANGEROUS LOAD
Accurate XMR 5744                   87.4     23.0     1.49    2259    99.2    55000    7346   0.897  !DANGEROUS LOAD
Hodgdon H335                       105.0     31.1     2.01    2252    91.1    49566    8364   0.922  !DANGEROUS LOAD
Hodgdon H322                       105.0     28.6     1.85    2244    93.9    48632    8111   0.928  !DANGEROUS LOAD
Hodgdon H110                        83.1     24.1     1.56    2242   100.0    55000    6755   0.916  !DANGEROUS LOAD
Hodgdon H4227                       96.3     23.6     1.53    2240   100.0    55000    6672   0.898  !DANGEROUS LOAD

Posted: 6/29/2006 10:31:41 PM EDT

[#15]

Thanks Randall. That is more than I expected. It seems to be a pretty efficient cartridge. Best of all I see powders that I already use. I do like the idea of this round. You will probably hear from me in the near future.

Posted: 7/22/2006 2:11:55 PM EDT

[#16]

What do subsonic loads look like? Specifically, I'm either going to build to a 12 inch barreled AR-15 SBR or a 16 inch rifle. My interest is heavy stable bullets at 100 to 200 yards with shorter and longer distances being a minor concern.

Thanks!

Posted: 7/22/2006 7:04:38 PM EDT

[#17]

Quoted:
What do subsonic loads look like?

Subsonic loads are the domain of the 300x221.
It's the "right tool for the job"

Posted: 7/22/2006 7:34:13 PM EDT

[#18]

I agree but, I want one .30 cal AR-15 platform not two. With 240 grain projectiles out of a short barrel, it would seem that this round would work pretty well. I would have the advantage of being able to swap magazines and go from a pest popper to something that could reach out a little further and hit a little harder.

Posted: 7/24/2006 1:51:43 PM EDT

[#19]

If anyone is curious here's a good article on the .30 Herrett with a section comparing it to the 7.62x39. I'm more interested in the .30 HRT now...

Posted: 7/24/2006 7:17:29 PM EDT

[#20]

I have two barrels sitting here, one new, the other used for less than 20 rounds. I can dig up full specs if desired and IM or EM for a price.

Posted: 7/25/2006 6:11:43 PM EDT

[#21]

My only problem with getting a .30 HRT is I don't reload. I am getting a reloading press in September (my birthday) and I'm looking for a reloading project. The 6.5 MPC was my original choice but let's face it, it's not going to go anywhere so on to something else.

According to the article, the .30 Herrett was designed to be shot out of 10" contender barrels so the .30 HRT should be a good choice for someone wanting to do an SBR or say a 14.5" barrel with permanently attached muzzle brake

.

It's a pretty neat round...

Posted: 7/25/2006 6:19:42 PM EDT

[#22]

Quoted:
My only problem with getting a .30 HRT is I don't reload. I am getting a reloading press in September (my birthday) and I'm looking for a reloading project. The 6.5 MPC was my original choice but let's face it, it's not going to go anywhere so on to something else.

According to the article, the .30 Herrett was designed to be shot out of 10" contender barrels so the .30 HRT should be a good choice for someone wanting to do an SBR or say a 14.5" barrel with permanently attached muzzle brake

.

It's a pretty neat round...

I bet if you asked nicely, Reed would form some brass and load it for the 30HRT.
Then you could buy factory ammo right away and SAVE THE BRASS for later when you have your press.
Good news is that 30 Herrett dies can be had for $10-$15 if you watch eBay and gun shows.

[ARCHIVED THREAD] - .30 HRT info?

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