H335 Results, Anyone Have a Guess What's going on?

[Texas10]

Apologies for the long post, Guys. In need of some school'n here.

Started Load development with my Savage 12FV and (not new) Criterion 26" 8 twist barrel in 223 Rem. Been shooting this awhile but decided to try out the Hornaday 52 gr. HPBT Match and H335, CCI400 and Winchester brass on it's 12 cycle. Never tried H335 before but had an unopened pound sitting in the cabinet so...what the heck?

Sierra manual lists this combination for it's accuracy load, 26.9 grs at 3300 fps. with a maximum load of 27.6 grs. I deviated from my normal routine of start low and work up looking for all nodes. I thought I had a pretty good idea how it would shoot in my rifle.

Loaded up 10 sighters at 26.9 grains and -.010 off the lands which gave me a much shorter (2.170) OAL than the Sierra book of 2.250. Nevertheless, the charge only filled the case to near the bottom of the shoulder, so plenty of room.

Began shooting with a cold barrel and Magnetospeed attached, 86 F, winds 8 to 12 and boxing the compass (switching from all directions). First shot when straight into the 1" dot at 100 yds, at 3479 fps, which is 179 fps faster than book and sped up with successive shots. All followed the first into the dot.

1 3479
2 3511
3 3520 10 min break, scratch head, record velocities.
4 3506
5 3527
6 3547 Cease Fire break, marvel at target, but no one else there.
7 3508
8 3532
9 3563 Pierced primer, disassembled bolt
10 3518

Average speed 3521, SD 25, ES 84

Barrel never got that warm, due to Cease Fire and breaks, but you can see a definite pattern.

By the 9th round I pierced a primer and had to disassemble the bolt to remove the piece of primer cup jamming my firing pin. Group measured .6 moa for nine rounds with the 10th taking it out to .9 moa after the bolt disassembly. A pretty good start aside from the extreme velocity, but never got to the rounds exploring further towards the lands before I quit the test due to primer blanking.

I think I see ignition issues that maybe a CCI450 or Rem 7 1/2 might remedy, and no doubt I'll cut back on the charge too. I've read that ball powder is hard to light and magnum primers are standard. Any comments or experiences on this powder and primer would be appreciated.

Any opinions/ experiences regarding H335 being extremely temperature sensitive?

BTW: I measured the Sierra 52 gr p/n 1400 and compared it to the 52 HPBT Match. They were identical in diameter and bearing length as near as I could tell.

Any help to explain this experience would be appreciated. This barrel is not known by me to be exceptionally fast. I typically shoot 69 to 73 grain bullets out of this barrel and get expected results.

 

[GrocMax]

That seems like an awful high charge weight of 335, sure it didn't say BLC2? The online Hodgdon data shows max charge of 26.0 for a 53 Sierra HP. I recall some of the older Sierra manuals seemed to have some very stout max charges in several calibers.

400's blank on high pressure loads, try the 7 1/2 and 450. 7 1/2's work well with ball powders in my experience.

 

[SSL]

I have always used H335's brother H322 with standard small rifle primers in .223, .17 Remington and 7mm BR with no ignition issues even with hot loads. Magnum primers may be your problem.

 

[GrocMax]

400 is not a magnum primer, the 450 is.

 

[SSL]

Sorry...misread the number!

 

[TheOtherZilla]

I use 26.5 H335, Rem 7-1/2 primer in my 223, with 52 or 53 Sierra's. No problems here, and it is an excellent load. Also a Savage 12 FV with factory barrel.

http://accurateshooter.net/Downloads/sierra223rembolt.pdf

 

[drover]

H335 is very temperature sensitive, it is not unusual to encounter the problems you are having when using max or near max loads. The fact that velocities are increasing with each successive shot is letting you know that the powder is getting warm enough to increase pressures.
Your load is .9 grain over max load listed in the Hodgdon manual, so you need to back off and work up. Another problem area is that you used data for a Sierra bullet but were using a Hornady bullet - once again you need to back down and work you to the max load.
The fact that you are getting above max velocities is a major clue that you are overpressure on your loads, pressure = velocity, it is as simple as that.

H335 is a great powder, it gives the best accuracy in all of my 223's but loads developed on a cool day can be problematic if the ambient temperature is higher than the temp the load was developed at. Also if the cartridge sets in a hot chamber very long the temperature will rapidly transfer to the cartridge. One of these days after you have shot 5 or even better 10 rounds in fairly rapid sucession put a cartridge in a chamber for a minute then remove it and feel how hot the case is.

drover

 

[AckleymanII]

Texas10, use a thick cup primer.

I use 7 1/2, and 450's blow the groups.

I consider 26.5 a max load, so back down to 25.5 and work up.

You probably have a long throat, so touching the lands maybe out of the question.

 

[ranger3]

When I use h335 in my 204, I leave the ammo in my cooler and retrieve it single shot. Problem solved. It's incredibly accurate under those conditions however if I leave it out and the Sunshine hits it or even if it's warm it does not shoot well.

 

[Jackal2016]

Well I see 2 things that you are using that aren't weren't tested in Sierra's load data, the bullet as well as the brass.
Hornady's book lists max 25.4 grains for that bullet that the coincidentally tested with Winchester brass.
So, according to Hornady's data, you were over their MAX by 1.5 grains.
Always work a load up as in many cases the brass used for their development is not the same as yours, as well as test barrel lengths and twist rates. Same goes for any component substitution.

 

[snowpro440]

Maybe it's your brass, not sized properly to the chamber and the hold and trigger pull on the gun , as 25-26gr. usually works well.

 

[BoydAllen]

A couple of things to think about: You should have started low and worked up.
One thing that can matter, that many do not think about is that powders only have a linear charge to pressure relationship over a given range. If you step out of that range, things may get ugly fast. If you let a round stay in the chamber of a barrel for very long it will pick up heat that will increase pressure. It is better to leave the bolt open with the round in the action but not in the chamber until just before you are ready to shoot. This sort of thing typically happens while waiting for a favorable wind to return. In small cases differences in capacity that show up as differences in weight can have a major effect on the pressure from a given charge. One of the advantages to loading at the range is that you have little reason to do the kind of guessing that you did. Finally, someone said that using 450s blew up his groups. Generally a hotter primer will produce more pressure and from that more velocity. Essentially what happened is that the substitution took the load out of tune. To get reliable results you will need to do a mini-workup with each primer targeted at producing the same velocity as a known accurate load.

 

[Texas10]

Thanks for the replies, guys. The essence of my post was a question regarding excessive velocity. Not just a little excessive, nearly 200 fps over Sierra book and a huge ES. What I am questioning is primer ignition. Is it poor? SHOULD I go 450's or BR-4 or REM 7 1/2 and if so, why? Is H335 sensitive to temp and pressure?

FWIW: Bolt is left open, cartridge is loaded and fired within 30 sec. NOT heat soaking while waiting for wind conditions. And yes, made an ASSumption regarding a new powder I'd never used. Mea Culpa. But I stopped when pressures started to become extreme. No ejector marks or case swipes, so not that bad. Not like we all don't go there, ever.

As for throat length, these bullets are seated into the case further than Sierra spec. so decreased case volume is possibly a factor.

So here is where I am today. I can reduce the load a bit, change the primer for better ignition and enjoy a very fast load with exceptional accuracy and consistency.

I have the BR-4's and 450's. I'll have to find the Rem 7 1/2's. I also have Federal Small Rifle and Small Rifle Match. For those who shoot H335 in 223 Rem, what do you recommend?

Thanks again for all the fine advise. You guy's are the best!

 

[nmkid]

I use H-335 and I have never settled above 25.0 grs. That's max. for my rifle. At 25.3 I got funny looking primers while searching for a load.

 

[hikfromstik]

I had similar problems with H335 . I loaded some winter loads and loaded 0.3gn below Sierra's max (223) semi auto data . It warmed up a bit and I started blowing primers . The rem 7 1/2 primers were more accurate than the cci450s in my setup . Ymmv

 

[SBS]

Yes, H335 is very temp. sensitive. Try to develop your load in the temp. you are going to be shooting. I use Rem. 7/12's; they work well with H335. Another problem I have had is considerable variation in burning rate with different lots of military surplus H335. You didn't mention if it was surplus or current production, so don't know if this is a contributor. A couple of years ago, I changed from 1 lot to another in the middle of loading for a PD hunt without checking the load. I would up piercing primers after any 5 shot string and having to let it cool before another 5. Quit that pretty quick and when home, checked velocities and had to reduce it nearly 1 1/2 gr. for the same velocity as I was getting with the older lot. High extreme spreads such as you experienced can also be a symptom of high pressure. Rem. 7 1/2, CCI BR-4 and 450 primers all have harder cups than Win. or Fed. and may ignite ball powder more consistently.

 

[nmkid]

Another problem I have with H-335...It's boring

 

[boltfluter]

Rem 7.5 and H335 is a match made in heaven. Your first load was over max. Back it down. Good luck.

Paul

 

[varmintshooter]

By loading shorter length than book length you end up with less case volume which would cause pressure to spike. Book loads are a suggestion and any changes can make a difference

 

[jepp2]

In need of some school'n here.

Lots of great suggestions here already listed. I also find in Win 223 brass it has ~ 1.0 gr water capacity less than most other brass.

There are very good reasons why the recommendation is to reduce the max suggested load by 10% and work your way up. And you have first hand experience at what can happen when you take short cuts. No matter your loading experience level, the safety recommendations always apply.